Carbon black-graft polymer, method for production thereof, and use thereof

ABSTRACT

A carbon black-graft polymer, produced by causing a polymer possessing within the molecular unit thereof at least one reactive group selected from the class consisting of aziridine group, oxazoline group. N-hydroxyalkylamide group, epoxy group, and thioepoxy group to react with carbon black. The polymer can be used as a toner for electrostatically charged image, resin composition, coating composition, ink for thermographic transfer, coating agent for magnetic recording medium, rubber composition, and carbon black dispersion and the like.

This application is a divisional of application Ser. No. 373,234, filedJune 29, 1989, which is a divisional of application Ser. No. 134,319,filed Dec. 16, 1987.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a novel carbon black-graft polymer, a methodfor the production thereof, and use thereof. More particularly, thisinvention relates to a carbon black-graft polymer produced by thereaction of a polymer possessing a specific reactive group with carbonblack and useful in toner for developing electrostatically chargedimages, resin composition, coating composition, ink for thermographictransfer, coating agent for thermographic transfer ink ribbon,back-coating agent for magnetic recording medium, rubber composition,and carbon black dispersion, a method for the production of the polymer,and use thereof.

2. Description of the Prior Art

Carbon black excels in coloring property, electroconductivity,weatherability, chemical resistance, etc. and, because of thesefeatures, has been finding extensive utility in various applications asreinforcing agents and fillers for plastics and elastomers. Since carbonblack by nature comes in powdery or granular form, it is rarely used byitself. It is enabled to manifest the characteristic features such asrubber or resin or in a liquid such as water or thereof by beinguniformly dispersed in a solid substance solvent.

The affinity of carbon black for other substances such as organicmacromolecular compound, water, and organic solvent is weak as comparedwith the cohesive force generated between the particles of carbon black.It is extremely difficult, therefore, for carbon black to be uniformlymixed with or dispersed in other substances under ordinary mixing ordispersing conditions.

For the solution of this problem, many methods are being studied whichare directed to enabling carbon black to be uniformly mixed with ordispersed in a solid or liquid substrate by coating the surface ofcarbon black with a varying surfactant or resin thereby enhancing theaffinity of carbon black for the substrate.

Particularly, the carbon black-graft polymer which is obtained bypolymerizing a polymerizable monomer in the presence of carbon black hasbeen attracting attention because the hydrophilicity and/or olephilicitythereof can be suitably varied by suitably selecting the kind of thepolymerizable monomer.

Methods for the production of the carbon black-graft polymer aredisclosed in Japanese Patent Publications Nos. SHO 42(1967)-22,047, SHO44(1969)-3,826, and SHO 45(1970)-17,284, and U.S. Pat. No. 3,557,040,for example. These methods, however, produce carbon black-graft polymerof their species in low yields falling on the order of several toten-odd percent. Most of these products occur in the form of vinyl typehomopolymers and betray very poor efficiency of the surface treatmentgiven to carbon black. The methods, therefore, have not improved theaffinity of carbon black for other substances so much as are expected.Frequently, the conditions in which these products are dispersed insubstrates are varied by mixing or dispersing conditions.

An object of this invention, therefore, is to provide a novel carbonblack-graft polymer, a method for the production thereof, and usethereof.

Another object of this invention is to provide a carbon black-graftpolymer useful in toner for developing electrostatically charged images,resin composition, coating composition, ink for thermographic transfer,coating agent for thermographic transfer ink ribbon, back-coating agentfor magnetic recording medium, rubber composition, and carbon blackdispersion, a method for the production of the polymer, and use thereof.

SUMMARY OF THE INVENTION

The objects described above are accomplished by a carbon black-graftpolymer, produced by a procedure which comprises causing a polymerpossessing in the molecular unit thereof at least one reactive groupselected from the class consisting of aziridine group, oxazoline group,N-hydroxyalkylamide group, epoxy group, and thioepoxy group to reactwith carbon black.

Further, these objects are accomplished by a method for the productionof a carbon black-graft polymer, which comprises causing a polymerpossessing in the molecular unit thereof at least one reactive groupselected from the class consisting of aziridine group, oxazoline group,N-hydroxyalkylamide group, epoxy group, and thioepoxy group to reactwith carbon black at a temperature in the range of 20° to 350° C.

The carbon black-graft polymer can be used by itself as a toner fordeveloping electrostatically charged images. It can also be used ascombined with various resin binders, rubbers, and solvents, in a widevariety of applications such as to a toner for developingelectrostatically charged images, thermoplastic resin composition,thermosetting resin composition, coating composition, rubbercomposition, thermographic ink, coating agent for thermographic inkribbon, back-coating agent for magnetic recording medium, rubbercomposition, and carbon black dispersion.

We have found that a polymer possessing a specific reactive group withinthe molecular unit thereof reacts highly efficiently with the functionalgroup on the surface of carbon black, that the carbon black-graftpolymer produced by the reaction shows highly desirable dispersibilityin various substances, and that a carbon black-graft polymer ofparticularly high despersibility can be easily produced by selectingspecific reaction condition.

DESCRIPTION OF THE PREFERRED EMBODIMENT

This invention is directed to a carbon black-graft polymer produced by aproduce which comprises causing a polymer possessing within themolecular unit thereof at least one reactive group selected from theclass consisting of aziridine group, oxazoline group,N-hydroxyalkylamide group, epoxy group, and thioepoxy group (hereinafterreferred to as "polymer (A) possessing a reactive group") to react withcarbon black. As the carbon black used in the present invention, theremay be used any kinds of carbon black such as furnace black, channelblack, acetylene black, thermal black, lamp black, etc.

The polymer (A) possessing a reactive group embraces such polymers asvinyl type polymers, polyesters, and polyethers which possess within themolecular unit thereof at least one reactive group selected from theclass consisting of aziridine group, oxazoline group,N-hydroxyalkylamide group, epoxy group, and thioepoxy group. The groupwhich can react with the functional group on the surface of carbon blackis not limited to the reactive group defined above. When a polymerpossessing a group other than the reactive group defined above is used,the reaction must be preceded by a step for giving a pretreatment to thecarbon black.

As means of producing the polymer (A) possessing the reactivity, therecan be cited (1) a method which causes a polymerizable monomer (a)possessing the reactive group in the molecular unit thereof to bepolymerized (hereinafter referred to monomer (a)), when necessary, incombination with other polymerizable monomer (b) (hereinafter referredto monomer (b)), (2) a method which causes a compound (c) possessing thereactive group (hereinafter referred to compound (c)) in the molecularunit thereof to react with a polymer (d) capable of reacting with thecompound (hereinafter referred to polymer (d)) to effect introduction ofthe reactive group in the polymer, and (3) a method which causes in thepolymer (A) possessing the reactivity by a conventional method using apolymer (e) possessing the reactive group other than said reactive group(hereinafter referred to polymer (e)).

As examples of the polymerizable monomer possessing the aforementionedreactive group (a) which can be used in the method (1), there can becited aziridine group-containing polymerizable monomers represented bythe following formulas: ##STR1## oxazoline group-containingpolymerizable monomers such as 2-vinyl-2-oxazoline,2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline,2-vinyl-4-ethyl-2-oxazoline, 2-vinyl-5-ethyl-2-oxazoline,2-Isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline,2-isopropenyl-5-methyl-2-oxazoline, 2-isopropenyl-4-ethyl-2-oxazoline,2-isopropenyl-5-ethyl-2-oxazoline, and2-isopropenyl-4,5-dimethyl-2-oxazoline; N-hydroxy alkylamidegroup-containing polymerizable monomers such as N-hydroxymethylacrylamide, N-hydroxyethyl acrylamide, N-hydroxybutyl acrylamide,N-hydroxyisobutyl acrylamide, N-hydroxy-2-ethylhexyl acrylamide,N-hydroxycyclohexyl acrylamide, N-hydroxymethyl methacrylamide,N-hydroxyethyl methacrylamide, N-hydroxybutyl methacrylamide,N-hydroxyisobutyl methacrylamide, N-hydroxy-2-ethylhexyl methacrylamide,and N-hydroxycyclohexyl methacrylamide; epoxy group-containingpolymerizable monomers represented by the following formulas: ##STR2##wherein R¹ stands for a hydrogen atom or a methyl group and n for 0 oran integer in the range of 1 to 20; and thioepoxy group-containingpolymerizable monomers represented by the following formulas: ##STR3##wherein R¹ and n have the same meanings as defined above in the case ofthe epoxy group-containing polymerizable monomers; and a thioepoxy groupcontaining polymerizable monomer. One member or a mixture of two or moremembers selected from the group of monomers cited above can be suitablyused.

The monomer which (b) is optionally used in combination with the monomer(a) in the process (1) is not specifically restricted so long as itmeets the sole requirement that it should be copolymerizable with themonomer (a). As examples of the monomer which answer the description,there can be cited styrene type monomers such as styrene, o-methylstyrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-methoxystyrene, p-tert-butyl styrene, p-phenyl styrene, o-chlorostyrene,m-chlorostyrene, and p-chlorostyrene; acrylic acid or methacrylic acidtype monomers such as acrylic acid, methyl acrylate, ethyl acrylate,n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, stearyl acrylate,2-ethylhexyl acrylate, methacrylic acid, methyl methacrylate, ethylmethacrylate, propyl methacrylate, n-butyl methacrylate, isobutylmethacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexylmethacrylate, and stearyl methacrylate; and ethylene, propylene,butylene, vinyl chloride, vinyl acetate, acrylonitrile, acrylamide,methacrylamide, and N-vinyl pyrrolidone. One member or a mixture of twoor more members selected from the monomers cited above may be suitablyused.

In accordance with the method of (1), the polymer (A) possessing areactive group is obtained simply by polymerizing a polymer (a)optionally in combination with a monomer (b) by any of the conventionalmethods such as, for example, bulk polymerization method, suspensionpolymerization method, emulsion polymerization method, precipitationpolymerization method, and solution polymerization.

As examples of the compound (c) which is usable in the method of (2),there can be cited:

(2-1) Compounds possessing at least two groups of one kind of selectedfrom the aforementioned class of reactive groups within the molecularunit thereof,

(2-2) Compounds possessing at least two groups of different kindsselected from the aforementioned class of reactive groups within themolecular unit thereof, and

(2-3) Compounds possessing at least one group selected from theaforementioned class of reactive groups and other groups not belongingto the aforementioned class within the molecular unit thereof. The"other groups not belonging to the aforementioned class" mentioned in(2-3) are those other than aziridine group, oxazoline group,N-hydroxyalkylamide group, epoxy group, and thioepoxy group and capableof reacting with the groups contained in the polymer (d) which will bedescribed fully later on. For example, isocyanate group, amino group,carboxyl group, hydroxyl group, vinyl group, and halogen atom answer thedescription.

Example of the polymer (d) to be used in the method of (2) are vinyltype polymers, polyester, and polyethers which possess groups capable ofreacting with the compounds (c) set forth in the aforementioned items,(2-1) through (2-3). As examples of the group capable of reacting withthe compound (c), there can be cited hydroxyl group, phenolic hydroxylgroups, carboxyl group, quinone group, amino group, and epoxy group. Thepolymers possessing these groups can be easily obtained by any of theconventional procedures of polymerization such as radical polymerizationand polycondensation.

In accordance with the method of (2), the polymer (A) possessing areactive group is obtained by simply by causing reaction of the compound(c) and the polymer (d) under conditions selected so that at least onegroup of the aforementioned class of reactive groups will remainunaltered.

The polymer (e) in the method of (3) is a polymer which possesses withinthe molecular unit thereof a vinyl group, carboxyl group, a chlorohydringroup, or a glycol group, i.e. a group capable of being converted intoan aziridine group, an oxazoline group, an N-hydroxyalkylamide group, anepoxy group, or a thioepoxy group. This polymer can be easily convertedby the conventional method into the group (A) possessing an aziridinegroup, an oxazoline group, an N-hydroxyalkylamide group, an epoxy groupand/or a thioepoxy group.

In the present invention, the polymer (A) is suitably selected,depending on the particular property such as, for example,hydrophilicity, oleophilicity, or other form of affinity which isdesired to be imparted to the carbon black-graft polymer. Whenhydrophilicity is desired to be imparted, for example, a vinyl typepolymer or a polyester which has acrylic acid as a main componentthereof is advantageously used. When oleophilicity is to be imparted, avinyl type polymer or a polyester which has styrene as a main componentthereof is used advantageously. The molecular weight of the polymer (A)is not specifically limited. From the standpoint of the conspicuity ofthe effect of treatment on carbon black and the operational convenienceduring the course of the reaction, however, the polymer (A) is desiredto possess a number average molecular weight in the range of 500 to1,000,000, more advantageously 1,000 to 500,000, and most advantageously2,000 to 100,000. Among the reactive group of the polymer (A), aziridinegroup, oxazoline group and N-hydroxyalkylamide group are the mostpreferable, and the meanings to be used such polymer possessingreactivity (A) is to react carbon black with the polymer (A) in highgraft efficiency even under a mild condition to obtain carbon blackgraft polymer excellent in dispersibility to various substances in spiteof kind and state of carbon black.

When the reactive group is an epoxy group or a thioepoxy group, thereactivity of the reactive group is lowered in proportion as the pHvalue of carbon black is high. For the carbon black to be usedeffectively, therefore, it is desired to have a pH value of not morethan 8, preferably not more than 6. The test of carbon black for the pHvalue is performed by the method defined by Japanese Industrial Standard(JIS) K 6221. Though the polymer (A) must contain as a reactive group atleast one epoxy group or thioepoxy group on the average in the molecularunit thereof, the polymer gains in viscosity and loses operationalefficiency during the reaction thereof with carbon black and the carbonblack-graft polymer obtained by the reaction loses dispersibility inother substances in proportion as the reactive group content of thepolymer increases. Thus, the average number of reactive groups containedin the molecular unit is desired to fall in the range of 1 to 5,preferably 1 to 2. Most desirably, the polymer (A) contains one epoxygroup or thioepoxy group.

The carbon black-graft polymer of this invention is produced by thereaction of the polymer (A) possessing a reactive group upon carbonblack. It has the polymer (A) bonded with extremely high efficiency bygrafting to carbon black. This reaction can be effected by any ofvarious method. For example, the method which comprises causing thepolymer (A) possessing a reactive group and obtained by theaforementioned method of (1) or (2) to react with carbon black may beused. Alternatively, a step for obtaining the polymer (A) possessing areactive group by working the method of (1) or (2) in the presence ofcarbon black and a step for effecting reaction of the polymer (A) withcarbon black may be combined as one method. For the purpose of obtainingthe carbon black-graft polymer with high graft efficiency, the reactionis desired to be carried out by the former of the two methods justcited.

The amount of the polymer (A) possessing a reactive group to be used inthe reaction with carbon black can be freely selected to suit thepurpose for which the produced carbon black-graft polymer is used. Toensure thorough manifestation of the effect in improving thedispersibility of carbon black-graft polymer in various substances andavoid impairing the characteristic properties inherent in carbon black,the amount of the polymer (A) is advantageously selected in the range of1 to 3,000 parts by weight, more desirably 5 to 1,000 parts by weight,and most desirably 50 to 500 parts by weight, based on 100 parts byweight of carbon black.

This invention also provides a method for easily producing carbonblack-graft polymer of notably enhanced dispersibility in varioussubstances. This method of production is effected by stirring carbonblack and the polymer (A) possessing a reactive group at a temperaturein the range of 20° to 350° , preferably 50° to 300° C. Further, it canbe attained by kneading carbon black and the polymer (A) possessingreactivity in the range of 0.01 to 20 kg.m, preferably 0.1 to 10 kg.m oftorque value, per 50 cc of total amount. The carbon black-graft polymerproduced by the method of this invention possesses highly improvedproperties because the carbon black used in the state of secondaryagglomeration as a raw material, while being stirred with the polymerfor reaction, is efficiently disintegrated and transformed into discreteparticles minute and uniform in diameter and, what is more, the reactionconsequently induced proceeds with improved efficiency. When thereaction temperature exceeds 350° C., there ensues a disadvantage thatthe polymer component of the reaction system undergoes degeneration.When the torque value exceeds 50 kg m, per 50 cc of total amount, thereensues a disadvantage such as deterioration by cut of polymer (A).

In the method of the present invention, the reaction of carbon blackwith the polymer (A) possessing a reactive group may proceed exclusivelybetween the two components mentioned or in the presence of othersubstances such as a polymer component other than the Polymer (A)possessing a reactive group, a polymerizable monomer, an organicsolvent, and water. In one typical way of working the method of thepresent invention, the carbon black-graft polymer of the presentinvention is obtained by preparing a mixture consisting of 100 parts byweight of carbon black, 1 to 3,000 parts by weight, preferably 5 to1,000 parts by weight, of the polymer (A) possessing a reactive group, 0to 1,000 parts by weight of a polymer possessing no reactive group, 0 to200 parts by weight of a polymerizable monomer, and 0 to 1,000 parts byweight of an organic solvent and stirring the mixture at a temperaturein the range of 20° to 350° C., preferably 50° to 300° C.

The carbon black-graft polymer of the present invention is produced bythe reaction of the polymer (A) possessing a reactive group with carbonblack. Since the reactive group in the polymer (A) possesses highreactivity with the functional group on the surface of carbon black, thepolymer (A) is grafted with high efficiency to the surface of carbonblack. Only so long as the polymer (A) possesses a reactive groupconforming with the definition given in this invention, it can be freelyselected without any discrimination on account of composition and kindso as to impart to the carbon black varying properties suiting theintended application of the product. The carbon black-graft polymerconsequently produced possesses improved affinity for various substancesand excels in dispersibility in such substances as organicmacromolecular compounds, water, and organic solvents and, therefore,can be advantageously used as coloring agents for inks, toners incopying machines, coating materials, and plastic molding materials andas modifying agents for various macromolecular compounds. Further inaccordance with the method of this invention, the carbon black-graftproperties represented by dispersibility can be produced by a simpleprocedure of merely stirring the polymer (A) possessing a reactive groupwith carbon black under application of heat. Thus, the method of thepresent invention for the production of carbon black-graft polymerproves to be highly advantageous from the economic point of view.

The toner of the present invention to be used for the development ofelectrostatic charge images is a product incorporating therein thecarbon black-graft polymer described above. The carbon black-graftpolymer by itself or a mixture of the carbon black-graft polymer with apolymer not answering the description of the polymer (A), on beingfinely pulverized, can be used without any further modification as thetoner of the present invention for the development of electrostaticcharge images. From the standpoint of the fixability of developedimages, the toner is desired to incorporate additionally therein thepolymer other than the polymer (A). It is particularly desirable thatthe polymer other than the polymer (A) is a thermoplastic polymer Thepolymer other than the polymer (A) may be mixed during and/or afterreaction of the carbon black with the polymer.

The carbon black content of the toner of the present invention for thedevelopment of electrostatic images charge is not specifically limitedbut can be selected in a wide range so as to suit the particular purposeof use. Generally, this content is in the range of 1 to 20% by weight,preferably 3 to 10% by weight, based on the total amount of the toner.The toner may suitably incorporate therein conventional additives suchas, for example, a charge controlling agent and an offset preventingagent.

For the toner of the present invention to be effectively used in theproduction of images with an electrophotographic developing system, itis generally used either in the form of a two-component developing agentobtained by mixing the toner with fine magnetic particles or in the formof a one-component developing agent obtained by causing the finemagnetic particles to be contained in the toner. The fine magneticparticles can be made of any material inherently magnetic or capable ofbeing magnetized. Examples of the material usable for the fine magneticparticles include such metals as iron, manganese, nickel, cobalt, andchromium and such ferromagnetic alloys as magnetite, maghemite, variousferrites, and manganese alloys.

In the case of the two-component developing agent, the fine magneticparticles are prepared with an average diameter in the range of 20 to100 microns, preferably 40 to 80 microns and are used as a carrier. Theamount of the fine magnetic particles to be used generally falls in therange of 70 to 99% by weight, preferably 90 to 97% by weight, based onthe total amount of the developing agent. In the case of theone-component developing agent, the fine magnetic particles preparedwith an average diameter approximately in the range of 0.05 to 5microns, preferably 0.1 to 2 microns, can be used. The amount of thefine magnetic particles to be used in this case generally fall in therange of 1.5 to 70% by weight, preferably 25 to 45% by weight, based onthe total amount of the developing agent.

Since the toner of this invention for the development of electrostaticcharge images used the carbon black-graft polymer obtained by the methodof this invention and, therefore, enjoys high homogeneity of dispersionof carbon black in the resin, the toner entails only slight liberationof carbon black during the course of fine pulverization, enjoys uniformdistribution of electric charge among the individual particles thereof,enables images to be stably developed in an unsweared form, andconsequently warrants production of visible images clear and sharp inoutline and rich in contrast. Thus, the toner of the present inventioncan be advantageously used for printing with a wide variety ofelectrophotographic developing devices such as, for example, copymachine, laser printer, LED (light-emitting diode) printer, and liquidcrystal printer.

Another use found for the carbon black-graft polymer is as coloringagents for thermoplastic resin and thermosetting resin.

Examples of the thermosetting resin for which the carbon black-graftpolymer of this invention is advantageously used as the coloring agentinclude unsaturated polyester resins obtained by dissolving unsaturatedpolyesters in polymerizable monomers represented by styrene, epoxyresins, diallyl phthalate resins, phenol resins, amino resinsrepresented by melamine resin, polyimide resins, and polyurethaneresins.

The combination of the carbon black-graft polymer and a thermosettingresin can be accomplished, for example, by a method which comprisesdirectly adding fine carbon black-graft polymer particles to thethermosetting resin and thoroughly mixing the two component by stirringor a method which comprises dispersing the fine carbon black-graftpolymer particles in a monomer such as, for example, styrene which iscopolymerizable with the thermosetting resin and thereafter mixing theresultant dispersion with the thermosetting resin. The proportion of thecarbon black-graft polymer to be used in the combination is in the rangeof 0.05 to 50% by weight, preferably 0.1 to 30% by weight, based on thetotal amount of the thermoplastic resin and the carbon black-graftpolymer. If this proportion is less than 0.05% by weight, then thethermosetting resin produced by the combination is deficient in coloringproperty, electroconductivity, heat resistance, wear resistance, andrepression of shrinkage. Conversely if this proportion is unduly large,there ensues a disadvantage that the characteristic properties of thethermoplastic resin are impaired.

In the thermosetting resin composition which is obtained as describedabove, since the polymer in the carbon black-graft polymer possessesaffinity for carbon black and this polymer, through suitable selectionof the composition itself, acquires affinity additionally for the resinof the matrix of the thermosetting resin composition, it is dispersedvery uniformly and stably in the composition so as to manifest anoutstanding effect in imparting to the produced composition suchdesirable qualities as uniformity of coloration, ability to inhibitstatic charging, resistance to heat, and wear resistance. Further, thepolymer component in the carbon black-graft polymer is enabled tomanifest an effect in alleviating the shrinkage of the matrix resinduring the course of thermal setting. Though the thermosetting resincomposition of the present invention can be effectively used in theunmodified form, it may be used in combination with fillers such ascalcium carbonate, silica sand, barium sulfate, and clay, reinforcingfibrous materials such as glass fibers, asbestos, hemp, vinylon fibers,carbon fibers, α-cellulose, and wood flour, tackifiers such as magnesiumoxide and magnesium hydroxide, and coloring agents to produce shapedarticles which are suitable as automobile parts, electric appliances,and household utensils.

Examples of the thermoplastic resin for which the carbon black-graftpolymr of the present invention is advantageously used includeunsaturated polyesters such as polyethylene terephthalate andpolybutylene terephthalate, acrylic resins such as methyl methacrylicresin, polycarbonates, polyimides, vinyl chloride polymers, styrenepolymers, polyamides, polyolefins, butyral resins, and polyurethanes.Among other thermoplastic resins enumerated above, unsaturatedpolyesters prove to be particularly desirable.

In the thermoplastic resin composition, the carbon black-graft polymerof the present invention is incorporated in an amount in the range of0.001 to 50% by weight, preferably 0.01 to 20% by weight, based on theamount of the composition. If the amount of the carbon black-graftpolymer added is less than 0.01% by weight, it is difficult for theproduced thermoplastic resin composition to acquire highly desirablesurface smoothness, homogeneity of texture, lubricity, antiblockingproperty, and antistatic property. Conversely, if the amount exceeds 50%by weight, the excess carbon black-graft polymer brings about an adverseeffect on the smoothness and strength of the resin composition when thiscomposition is fabricated in the form of film or fibers and causesbreakage of such film or fibers during the course of molding.

The incorporation of the carbon black-graft polymer in the thermoplasticresin such as, for example, a polyester can be effected by either of thefollowing methods.

(1) A method which comprises adding a carbon black-graft polymer to aninteresterification product of dimethyl terephthalate and ethyleneglycol and subjecting the resultant mixture to polycondensation therebyobtaining a polyester composition aimed at.

(2) A method which comprises preparing a polyester from dimethylterephthalate and ethylene glycol and mixing the polyester with thecarbon black-graft polymer by stirring.

Alternatively, the incorporation may be effected by directly combiningthe carbon black-graft polymer with the thermoplastic resin.

Because of the fact that a carbon black-graft polymer obtained by thespecific method is incorporated therein, the thermoplastic resincomposition of this invention is enabled to produce shaped articles suchas films and fibers which excel in lubricity, smoothness, antiblockingproperty, wear resistance, homogeneity, ability to prevent staticcharging, and workability. The polyester composition which accords withthe present invention, therefore, can be used as films for magnetictapes and wraps and as finished yarns.

Another use found for the carbon black-graft polymer is as a coatingcomposition. The binder to be used in the coating composition is athermoplastic resin, a thermosetting resin, or a reactive resin which isenabled by being applied on a varying substrate to form a coating filmthereon. One member or a mixing of two or more members selected from thegroup consisting of thermoplastic resins, thermosetting resins, andreactive resins can be used as the binder.

Among other usable thermoplastic resins, those having average molecularweights in the range of 1,000 to 1,000,000, preferably 2,000 to 500,000,prove to be particularly advantageous. As concrete examples of suchparticularly advantageous thermoplastic resins, there can be cited vinylchloride type resins such as vinyl chloride polymers and vinylchloride-vinylidene chloride copolymers: vinyl ester type resins such asvinyl acetate polymer, vinyl acetate-ethylene copolymer, and vinylacetate-methyl methacrylate copolymer, (meth)acrylic ester type resinssuch as (meth)acrylic ester (co)polymers, (meth)acrylicester-acrylonitrile copolymers, and (meth)acrylic ester-styrenecopolymers; styrene type resins such as styrene polymer,styrene-butadiene copolymer, and styrene-butadiene-acrylonitrilecopolymer; polyamide type resins such as poly(ε-caprolactam) and thecondensate of adipic acid and hexamethylene diamine; polyester typeresins such as the condensate of terephthalic acid and ehtylene glycoland the condensate of adipic acid and ethylene glycol; polyolefin typeresins such as polyethylene, chlorinated polypropylene, carboxylmodifiedpolyethylene, polyisobutylene, and polybutadiene; cellulose derivativessuch as cellulose acetate, cellulose propionate, and nitrocellulose; andbutyrol resins. These resins are available on the market or obtainableby the conventional method of syntheses.

The thermosetting resin or the reactive resin which is effectivelyusable as the binder for the coating composition is required to be suchthat it is enabled, either during or after the formation of a coating,to give rise to a cross-linked structure through addition reaction orcondensation reaction by virtue of application of heat, irradiation withan active energy ray, or desiccation. As concrete examples of thethermosetting resin or reactive resin, there can be cited phenol typeresins such as novolak resins and resol resins; amino type resins suchas uread resin, melamine resin, and benzoguanamine resin; various alkydresins; unsaturated polyester resins; curing acrylic type resins;urethane modified resins such as isocyanate group-containing polyestersand isocyanate group-containing polyethers; polyamine type resins, andepoxy resins.

The binder mentioned above must be selected so as to suit theadhesiveness and wettability exhibited to a substrate, and the rigidity,flexibility, chemical resistance, antifouling property, andweatherability required of the coating film. One member or a mixture oftwo or more members selected from the group of thermosetting resins andreactive resins is used in due consideration of the purpose for whichthe coating composition is used.

The carbon black-containing coating composition of the present inventioncontains the aforementioned carbon black-graft polymer and the binderand may be in the form of a mixture containing no solvent, a solution,or a dispersion. It can be obtained by any of the conventional methods.For example,

(1) A method which comprises preparing a solution of the binder in asuitable solvent (such as, for example, water, alcohol, acetone, ortoluene) and keeping the solution stirred and gradually adding theretothe carbon black-graft polymer.

(2) A method which comprises mixing a dispersion of the binder with thecarbon black-graft polymer.

(3) A method which comprises mixing the binder with the carbonblack-graft polymer and subsequently adding a suitable solvent to theresultant mixture.

(4) A method which comprises mixing a liquid binder capable of beingcured by a suitable method with the carbon black-graft polymer.

(5) A method which comprises carrying out the aforementioned workingexample of the production of the carbon black-graft polymer while using,as a polymer devoid of reactivity with carbon black, a polymer answeringthe description of the binder and subsequently adding a suitable solventto the resultant mixture cf the carbon black-graft polymer and thebinder.

Though the ratio of the carbon black-graft polymer and the binder to beused in the carbon black-containing coating composition is notspecifically restricted, it is proper for the purpose of enabling thecarbon black-containing coating composition to manifest thecharacteristec properties thereof thoroughly without impairing theproperties as a coating to limit the amount of carbon black contained inthe carbon black-graft polymer to the range of 1 to 300 parts by weight,preferably 5 to 100 parts by weight, based on 100 parts by weight of thebinder.

The carbon black-containing coating composition of the present inventionmay suitably incorporate therein, in addition to the aforementionedcomponents, the conventional additives for coating compositions inamounts out so large as to impair the intended effects of the producedcomposition. As examples of such additives usable advantageously in thecoating composition of this invention, there can be cited metallic soap,dispersion aids such as surfactants, film-forming aids, antistaticagents, defoaming agents, and inorganic filters such as silica, talc,calcium carbonate, and titanium dioxide.

The carbon black-containing coating composition of the present inventioncomprises the carbon black-graft polymer and the binder. Since thecarbon black-graft polymer is highly effective in dispersing the coatingcomposition in a liquid and is excellent in affinity for the binder, thecarbon black containing composition enjoys a long shelf stability lifeand, when applied on a various substrate, produces a coating whichpossesses a stable antistatic property and a uniform coloring propertyand excels in wear resistance, resistance to heat, antiblockingproperty, and lubricity.

The carbon black-graft polymer coating composition of the presentinvention, therefore, can be advantageously used to coat varioussubstrates such as molded plastic articles, metal articles, wood, paper,and inorganic materials for the purpose of protecting and modifying thesurfaces of such substrates.

The carbon black-graft polymer can be used as a carbon black dispersion.The carbon black dispersion of the present invention contains a carbonblack-graft polymer having a polymer (A) reactive with carbon blackgrafted on to the surface of carbon black. The polymer (A) possesses avery high grafting ratio to carbon black as compared with that which iscommon to the conventional grafting method and binds itself verystrongly to the surface of carbon black. Further, the polymer is allowedto possess a backbone selected from a wide variety of backbones. Thus,the polymer (A) is capable of freely, effectively, and economicallymodifying the surface properties of carbon black so as to suit theparticular dispersion solvent to be used or the purpose for which theproduced dispersion is used. The amount of the carbon black-graftpolymer to be dispersed is in the range of 1 to 80% by weight,preferably 5 to 60% by weight, based on the amount of the dispersion.The carbon black dispersion of the present invention, therefore, hascarbon black homogeneously dispersed microscopically therein and isuseful as a coloring agent in various applications. The carbon blackdispersion, either in the unmodified form or in a form combined suitablywith necessary components, can be used as an ink of highly stabledispersibility and richly coloring property in water or oil writingdevices, data recording devices, or printing devices. Further, thecarbon black dispersion of the present invention can be used as toningpigment pastes (black toner) for inks, coating materials, and plastics.It can be easily dispersed in inks, coating materials, and plasticswithout impairing the properties thereof.

The carbon black-graft polymer can be used as a rubber composition. Asthe rubber component for the rubber composition of the presentinvention, one member or a mixture of two or more members selected fromthe group consisting of rubbers such as natural rubber (NR),styrene-butadiene rubber (SBR), polybutadiene rubber (BR), polyisoprenerubber (IR), chloroprene rubber (CR), nitrile rubber (NBR), butyl rubber(IIR), ethylene-propylene rubber (EPM, EPDM), silicone rubber, fluorinerubber, and epichlorohydrin rubber (CHR), and styrene-butadiene typethermoplastic elastomers.

The rubber composition of the present invention is produced by theincorporation of a carbon black-graft polymer in a rubber component. Forthis production, it suffices to select the amount of the carbonblack-graft polymer in the range of 1 to 90% by weight, preferably 10 to70% by weight, based on the total amount of the rubber composition. Ifthe amount of the carbon black-graft polymer to be added is undulysmall, the effect of carbon black manifested in reinforcing the rubberis not sufficient so that the produced rubber composition permitsproduction of shaped articles of high mechanical properties only withdifficulty. Conversely if the amount is unduly large, the producedrubber composition poses problems concerning the kneadability and themechanical properties. When the amount of the carbon black graft-polymerto be added is selected within the aforementioned range, the rubbercomposition can be vested with the antistatic property andelectroconductivity suitable for the purpose for which the rubbercomposition is used.

The rubber composition of the present invention may incorporate thereinconventional additives such as reinforcing agent, filler, vulcanizer,vulcanization aid, vulcanization accelerator, softening agent,plasticizer, pigment, antioxidant, and ultra-violet absorbent to suitoccasion. The amounts of these additives to be used, the sequence oftheir addition, and the manner of their addition are matters for freechoice and need not be specifically restricted

The rubber composition of the present invention can be given any of thetreatments such as vulcanization normally adopted in the processing ofrubber compounds. These treatments are not specifically restricted.

Owing to the incorporation of the carbon black-graft polymer, the rubbercomposition of the present invention is excellent in kneadability,appearance of shaped products thereof, and mechanical properties. Therubber composition of the present invention, therefore, can beeffectively used in applications as to tires, belts, rolls, tubes,sandals, electric cables, mechanical articles, and industrial parts.

Since the carbon black-graft polymer is very easily dissolved anddispersed in the binder component of ink, it permits production of athermographic transfer ink having carbon black homogeneously dispersedmicroscopically therein. As examples of the binder component of thethermographic transfer ink, there can be cited natural and syntheticwaxes such as carnaruba wax, montan wax, paraffin wax, microcrystallinewax, oxide wax, low molecular polyethylene wax, and low molecularpolypropylene wax; and synthetic resins such as polysulfon ether,polycarbonates, polystyrene, silicone resin, and acrylic type resins.

The dispersion of the carbon black-graft polymer in the binder componentis very easily attained by merely mixing the two components under weakshear force with a stirring device such as, for example, a stirrerprovided with blades of a varying shape, a static mixer, or a meltmixer. This dispersion does not require a kneading action produced understrong shear force with a kneading device such as a ball mill or a rollmill. Optionally, this dispersion may be accomplished by causing thereaction of carbon black with the polymer (A) to proceed in the presenceof the binder of the ink. In this manner, the thermographic transfer inkcan be produced in a single process. When the polymer (A) itself isselected so as to serve effectively as the binder for the ink, thecarbon black-graft polymer can be used directly as the thermographictransfer ink without requiring incorporation therein of any otherbinder. Though the amount of carbon black in the thermographic transferink is not specifically restricted, it is generally selected in therange of 1 to 40% by weight, preferably 5 to 30% by weight. Thethermographic transfer ink may incorporate other wellknown additives,when necessary, in addition to the components mentioned above.

The thermographic transfer ink of the present invention can be appliedby any of the conventional devices such as hot melt coater, reverse rollcoater, and gravure roll coater on any of the substrates represented byPET film, polyimide film, condenser paper, silk cloth, and aluminum foilto produce thermographic transfer ink sheets of highly desirablequality.

The thermographic transfer ink of the present invention contains acarbon black-graft polymer having the polymer (A) reactive with carbonblack grafted on to the surface of carbon black. The polymer (A)possesses a very high grafting ratio to carbon black as compared withthat which is common to the conventional grafting method and bindsitself very strongly to the surface of carbon black. Further, thepolymer is allowed to possess a backbone selected from a wide variety ofbackbones. Thus, the polymer (A) is capable of freely, effectively andeconomically modifying the surface properties of carbon black so as tosuit the binder component of the ink to be used. Thus, the carbonblack-graft polymer of the present invention is extremely uniformlydispersed microscopically in the binder component of the thermographictransfer ink and the carbon black and the binder component of the inkexhibit very high affinity for each other through the medium of thepolymer (A). The images recorded with the thermographic transfer ink ofthe present invention, therefore, possess very high quality and enjoyoutstanding durability.

Yet another use found for the carbon black-graft polymer is as a coatingagent for the thermographic transfer ink ribbon. Examples of the bindercomponent for the ribbon coating agent include various known resins suchas vinyl chloride polymer, vinyl chloride-vinyl acetate copolymer,acrylic type resins, styrene polymer, polyurethane resins, and polyesterresins. The ribbon coating agent is obtained by adding carbonblack-graft polymer to the binder component of the kind mentioned aboveand thoroughly stirring the resultant mixture. The proportion of carbonblack-graft polymer to be added to the coating agent is in the range of1 to 60% by weight, preferably 5 to 40% by weight, based on the amountof the coating agent. The ribbon coating agent which is consequentlyobtained is applied on a substrate with any of the conventional devicessuch as roll coater, air knife coater, air doctor coater, and spraycoater, to give rise to a ribbon coating layer on the rear side thereof.

The carbon black-graft polymer in accordance with the present inventionis uniformly dispersed microscopically in a backcoat layer, and excelsin wear resistance without falling out of the carbon black.

The carbon black-graft polymer is very easily dissolved and dispersed inthe back coating agent and, therefore, permits production of a backcoating agent having carbon black uniformly dispersed microscopicallytherein. Examples of the binder component in the back coating agent foruse on the magnetic recording medium include vinyl cycloride typeresins, vinyl chloride-vinyl acetate copolymer type resins, acrylic typeresins, styrene type resins, polyurethane type resins, and polyestertype resins. The carbon black-graft polymer of the present invention canotherwise be dispersed in a solvent to produce a back coating agentwithout use of the binder component. The solution or dispersion of thecarbon black-graft polymer in the binder component and/or the solvent isgenerally attained simply by stirring the carbon black-graft polymer,the binder component, and/or the solvent at room temperature for aperiod of several minutes to some tens of minutes. It may be effected,when necessary, by kneading and dispersing the aforementioned componentsby the use of a roll mill, a sand mill, a ball mill, a supersonicdispersing machine, a disperser, or a homogenizer. The amount of thecarbon black-graft polymer to be incorporated in the back coating agentis in the range of 1 to 60% by weight, preferably 5 to 40% by weight.The back coating agent thus produced is applied on a substrate with anyof the known devices such as roll coater, air knife coater, air doctorcoater, and spray coater, to give rise to a back coating layer on therear side thereof.

Examples of the substrate to be used in the magnetic recording medium ofthe present invention include films, sheets, and tapes of polyester,cellulose acetate, and polyvinyl chloride. The magnetic recording layercan be formed by applying a coating agent containing a known magneticpowder or by vacuum depositing a magnetic substance, for example.

The magnetic recording medium of the present invention is provided witha back coating layer containing a carbon black-graft polymer having thepolymer (A) reactive with carbon black grafted on to the surface ofcarbon black. The polymer (A) possesses a very high grafting ratio tocarbon black as compared with that which is common to the conventionalgrafting method and binds itself very strongly to the surface of carbonblack. Further, the polymer is allowed to possess a backbone selectedfrom a wide variety of backbones. Thus, the polymer (A) is capable offreely, effectively, and economically modifying the surface propertiesof carbon black so as to suit the back coating agent to be used. Thecarbon black-graft polymer of the present invention is uniformlydispersed microscopically in the back coating layer and the carbon blackand the binder component come into close mutual contact. As the result,the back coating layer is extremely robust, does not suffer separationof carbon black, and excels in wear resistance. Since the magneticrecording medium of the present invention is thus provided with a backcoating layer of robust texture, it entails very little degradation ofquality even after repeated use over a protracted period.

Now, the present invention will be described more specifically belowwith reference to working examples. It should be noted, however, thatthe present invention is not limited by these examples. Wherever theterms "part" and "percentage (%)" are mentioned, they are invariablymeant respectively as "part by weight" and "% by weight."

EXAMPLE 1

A flask provided with a stirrer, an inert gas inlet tube, a refluxcondenser, and a thermometer was charged with 400 parts of deionizedwater having 0.2 part of polyvinyl alcohol dissolved therein. The flaskwas then charged with a mixture prepared in advance by dissolving 16parts of benzoyl peroxide in a polymerizable monomer consisting of 196parts of styrene and 4 parts of isopropenyl oxazoline. The contents ofthe flask were stirred at high rate to form a homogeneous suspension.Then the suspension, with nitrogen gas kept blown therein, was heated to80° C. and stirred at this temperature for 5 hours to effectpolymerization reaction and subsequently cooled to produce a polymersuspension. This polymer suspension was separated by filtration, washed,and then dried. Consequently, there was obtained a polymer possessing anoxazoline group as a reactive group. The molecular weight, Mn, of thispolymer, by the GPC test, was found to be 5,800.

In a mill (produced by Toyo Seiki KI.KI. and marketed under trademarkdesignation of "Laboplastomill"), 40 parts of the polymer possessing anoxazoline group as a reactive group and 20 parts of carbon black(produced by Mitsubishi Chemical Industries, Ltd. and Marketed undertrademark designation of "Carbon Black MA-600") were kneaded at 160° C.for 20 minutes at a rate of 100 rpm to effect reaction, then cooled, andpulverized, to produce a carbon black-graft polymer (1).

EXAMPLE 2

The same flask as used in Example 1 was charged with 200 parts oftoluene and 200 parts of methyl isobutyl ketone. The contents of theflask, with nitrogen gas kept blown therein, was heated to 80° C. To theheated contents of the flask, a mixture prepared in advance bydissolving 4 parts of benzoyl peroxide in a polymerizable monomerconsisting cf 190 parts of styrene and 10 parts of 2-(1-azyridinyl)ethylmethacrylate was added dropwise through a dropping funnel over a periodof 2 hours. The resultant mixture was further stirred for 5 hours toeffect polymerization reaction and then cooled, to produce a polymersolution. In 2,000 parts of methanol, 100 parts of this polymer solutionwas reprecipitated. The precipitate was removed and dried, to produce apolymer possessing an aziridine group as a reactive group. The molecularweight, Mn, of this polymer, by the GPC test, was found to be 3,000.

By following the procedure of Example 1, 20 parts of the polymerpossessing an aziridine group as a reactive group was caused to reactwith 20 parts of polystyrene (a product of Asahi Chemical Industry Co.,Ltd. having a molecular weight, Mn, of 4,000 and marketed undertrademark designation of "Styron-666") and 20 parts of the same carbonblack as used in Example 1. The resultant reaction mixture was cooledand pulverized to produce a carbon black-graft polymer (2).

EXAMPLE 3

A polymer possessing an N-hydroxyalkylamide group as a reactive groupwas obtained by following the procedure of Example 1, excepting 95 partsby weight of styrene, 3 parts of n-butyl acrylate, and 2 parts ofhydroxyethyl methacrylamide were used instead as polymerizable monomer.

The molecular weight, Mn, of this polymer, by the GPC test, was found tobe 6,200.

In the same mill as used in Example 1, 44 parts of the polymerpossessing an N-hydroxyalkylamide group as a reactive group and 20 partsof carbon black (MA-600) were kneaded at 180° C. for 40 minutes at arate of 100 rpm to effect reaction, then cooled, and pulverized, toproduce a carbon black-graft polymer (3).

EXAMPLE 4

The same flask as used in Example 1 was charged with 460 parts ofcyclohexane and 2 parts of a substance (produced by Kao Co., Ltd. andmarketed under trademark designation of "Leodol SP-S10). The contents ofthe flask, with nitrogen gas kept blown therein, were heated to 75° C.To the heated contents of the flask, a mixture prepared in advance byadding 140 parts of deionized water and 2 parts of ammonium persulfateto a polymerizable monomer consisting of 60 parts of acrylamide, 15.2parts of N-vinyl pyrrolidone, and 1.6 parts of N-hydroxyethylmethacrylamide was added dropwise through a dropping funnel over aperiod of 1.5 hours. The resultant mixture was stirred further for 0.5hour to effect polymerization reaction. The polymerization product wascooled, then stripped of cyclohexane, and dried at temperature of 80° to100° C. under a vacuum, to produce a polymer possessing aN-hydroxyalkylamide group as a reactive group. The molecular weight, Mn,of this polymer, by the GPC test, was found to be 12,000.

By following the procedure of Example 1, 45 parts of the polymerpossessing an N-hydroxyalkylamide group as a reactive group was causedto react with 15 parts of carbon black(produced by Mitsubishi ChemicalIndustries, Ltd. and marketed under trademark designation of "CarbonBlack MA-100R"). The resultant reaction mixture was cooled andpulverized to produce a carbon black-graft polymer (4).

EXAMPLE 5

The same flask as used in Example 1 was charged with 217 parts oftoluene. The toluene in the flask, with nitrogen gas kept blown therein,was heated to 90° C. To the heated toluene in the flask, a mixtureprepared in advance by dissolving 5.44 parts of thioglycolic acid and1.32 parts of azobisisobutyronitrile in a polymerizable monomerconsisting of 480 parts of styrene and 20 parts of n-butyl acrylate wasadded dropwise through a dropping funnel over a period of 2 hours. Theresultant mixture was further stirred for 5 hours to effectpolymerization reaction. The molecular weight, Mn, of this polymer, bythe GPC test, was found to be 9,500.

Then, 185.1 parts of the reaction product (a solution containing aprepolymer possessing a terminal carboxyl group) was caused to reactwith 2.95 parts of 2-p-phenylene-bis-2-oxazoline added thereto at 80° C.for 2 hours, to produce a solution (involatile content 70%) of a polymerpossessing a terminal oxazoline group as a reactive group.

In the same mill as used in Example 1, 57.1 parts of the solution(involatile content 70%) of the polymer possessing terminal oxazolinegroup and 20 parts of the same carbon black as used in Example 4 werekneaded at 160° C. for 20 minutes at a rate of 100 rpm to effectreaction. The resultant reaction product was stripped of the solvent,then cooled and pulverized to produce a carbon black-graft polymer (5).

EXAMPLE 6

An autoclave provided with a stirrer, a thermometer, and an ethyleneoxide feed unit was charged with 32 parts of methanol and 0.35 part ofsodium hydroxide. The contents of the autoclave were heated to 110° C.and kept stirred and maintained under pressure controlled between 5 and8 kg/cm². To the heated and stirred, the contents of the autoclave,88parts of ethylene oxide was added dropwise. The resultant mixture wasleft aging for 30 minutes and then heated to elevate the reactiontemperature to 150° C. To the heated mixture, 352 parts of ethyleneoxide was added dropwise over a period of 5 hours. Thereafter, theresultant mixture was left standing for 1 hour, to obtain a 10-moladduct of ethylene oxide possessing one methoxylated terminal. In thesame autoclave as used above, 47.2 parts of the 10-mol adduct ofuniterminally methoxylated ethylene oxide and 0.62 part of sodiumhydroxide were heated to 150° C. and 616 parts of ethylene oxide wasadded dropwise thereto over a period of 5 hours. Then, the resultantreaction was left aging for 1 hour to complete the polymerization andproduce uniterminally methoxylated polyethylene glycol.

In the same autoclave as used above, 400 parts of distilled water, 100parts of the uniterminally methoxylated polyethylene glycol, and 10parts of a platinum/palladium type catalyst were kept at a temperaturein the range of 90° to 95° C. and, with compressed air added from timeto time maintain the internal pressure at 10 kg/cm², the contents of theautoclave were stirred for 30 hours to effect reaction. Consequently,there was obtained an aqueous solution of polyethylene glycol possessingan acid number of 8.4 and modified at one terminal thereof with amethoxy group and the other terminal with a carboxyl group. Themolecular weight, Mn, of this polymer, by the GPC test, was found to be6,600. This aqueous solution of modified polyethylene glycol had thesolvent thereof displaced with diethylene glycol and then was adjustedto a volatile content of 33.3%. In the same flask as used in Example 1,300 parts of the diethylene glycol solution of uniterminallycarboxyl-modified polyethylene glycol was heated to 50° C. To the heateddiethylene glycol solution, 1.70 parts of 2-(1-aziridinyl)-2-oxazolinewas added dropwise thereto through a dropping funnel over a period of 30minutes. The resultant mixture was left reacting for 5 hours and thencooled, to produce a solution (involatile content 33.7%) of a polymerpossessing a uniterminal oxazoline group as a reactive group.

In the same flask as used in Example 1, 90 parts of the solution of thepolymer possessing an oxazoline group as a reactive group and 30 partsof carbon black(product of Mitsubishi Chemical Industry Co., Ltd. andmarketed under trademark designation of "Carbon Black #45") were leftreacting with each other at 100° C. for 5 hours, to produce a diethyleneglycol solution of carbon black-graft polymer (6).

EXAMPLE 7

In the same flask as used in Example 1, 200 parts of a terminal carboxylgroup-containing linear saturated polyester (a product of NipponShokubai Kagaku Kogyo Co., Ltd. possessing a molecular weight, Mn, of6,000 and an involatile content of 50%, marketed under trademarkdesignation of "Aroplaz OB-63") and 3.60 parts of2-p-phenylene-bis-2-oxazoline were left reacting at 110° C. for 2 hours,to produce a solution (involatile content 50%) of a polymer possessing aterminal oxazoline group as a reactive group. Under the same conditionsas in Example 5, 80.0 parts of the solution (involatile content 50%) ofthe polymer possessing a terminal oxazoline group and 20 parts of &hesame carbon black as used in Example 4 were kneaded to effect reaction,to produce a carbon black-graft polymer (7).

Control 1

In the same flask as used in Example 1, 48 parts of styrene and 12 partsof the same carbon black as used in Example 1 were heated to 140° C.,with nitrogen gas kept blown therein, and kept stirred at thistemperature for 5 hours to effect polymerization reaction and thencooled. The resultant reaction product was combined with 300 parts oftoluene and reprecipitated in 7000 parts of methanol, to produce acarbon black-graft polymer (1) for comparison. This carbon black-graftpolymer (1) for comparison was composed of 100 parts of carbon blackcomponent and 250 parts of polystyrene component.

Control 2

Under the same conditions as in Example 1, 45 parts of the samepolystyrene possessing no reactive group as used in Example 2 and 15parts of the same carbon black as used in Example 1 were kneaded, thencooled, and pulverized, to produce a carbon black-graft polymer (2) forcomparison in which the carbon black component and the polymer componentwere not substantially bonded to each other.

EXAMPLE 8

The carbon black-graft polymers (1) through (7) and the carbonblack-graft polymers (1) and (2) for comparison obtained in Examples 1through 7 and Controls 1 and 2 were tested for dispersibility in tolueneand water. The results were as shown in Table 1.

                  TABLE 1                                                         ______________________________________                                        Amount (parts) of   Dispersion                                                                              Dispersion                                      polymer per 100     in toluene                                                                              in water                                        parts of carbon black                                                                             (Note 1)  (Note 1)                                        ______________________________________                                        Example                                                                       1       200                 good    --                                        2       200       (Note 2)  good    --                                        3       220                 good    --                                        4       300                 --      good                                      5       200                 good    --                                        6       100                 --      good                                      7       200                 good    --                                        Control                                                                       1       250                 bad     --                                        2       300                 bad     --                                        3       0                   bad     bad                                       (Note 3)                                                                      ______________________________________                                         (Note 1) The condition of dispersion was evaluated with respect to a          dispersion having a carbon black content of 5%.                               (Note 2) Of the total of 200 parts of the polymer, a polymer possessed of     a reactive group accounted for 100 parts.                                     (Note 3) Control 3 represents an experiment exclusively using the same        carbon black as in Example 4.                                            

EXAMPLE 9

A flask provided with a stirrer, an inert gas inlet tube, a refluxcondenser, and a thermometer was charged with 400 parts of deionizedwater having 0.2 part of polyvinyl alcohol dissolved therein. The flaskwas further charged with a mixture prepared in advance by dissolving 16parts of benzoyl peroxide in a polymerizable monomer consisting of 194.9parts of styrene and 5.1 parts of glycidyl methacrylate. The contents ofthe flask were stirred at a high rate to form a homogeneous suspension.Then the suspension, with nitrogen gas kept blown therein, was heated to80° C., stirred at this temperature for 5 hours to effect polymerizationreaction, and then cooled, to produce a polymer suspension.

This polymer suspension was separated by filtration, washed, and thendried, to produce a polymer possessing one epoxy on the average as areactive group in the molecular unit thereof. The molecular weight, Mn,of this polymer, by the GPC test, was found to be 5,500.

In the same mill as used in Example 1, 40 parts of the polymerpossessing one epoxy group on the average as a reactive group in themolecular unit and 20 parts of the same carbon black as used in Example4 were kneaded at 160° C. for 60 minutes at a rate of 100 rpm under atorque value of 1 kg.m per 50cc to effect reaction and then cooled andpulverized, to produce a carbon black-graft polymer (8).

EXAMPLE 10

The same flask as used in Example 9 was charged with 400 parts ofdeionized water having 0.2 part of polyvinyl alcohol dissolved therein.It was further charged with a mixture prepared in advance by dissolving16 parts of benzoyl peroxide in a polymerizable monomer consisting of100 parts of methyl methacrylate, 94.3 parts of butyl acrylate, and 5.7parts of 2,3-epithiopropyl methacrylate. Then the contents of the flaskwere stirred at high rate to product a homogeneous suspension. Then, thesuspension, with nitrogen gas kept blown therein, was heated to 80° C.and kept stirred at this temperature for 5 hours to effectpolymerization reaction and subsequently cooled, to produce a polymersuspension. This polymer suspension was separated by filtration, washed,and then dried to produce a polymer possessing one thioepoxy group onthe average as a reactive group in the molecular unit. The molecularweight, Mn, of this polymer, by the GPC test, was found to be 5,800.

In the same procedure as in Example 9, 20 parts of the polymerpossessing one thioepoxy group on the average as a reactive group in themolecular unit, 20 parts of the same polystyrene as used in Example 2and 20 parts of the same carbon black as used in Example 9 were allowedto react with each other. The resultant reaction mixture was cooled andpulverized to produce a carbon black-graft polymer (9).

EXAMPLE 11

In an autoclave provided with a stirrer, a thermometer, and an ethyleneoxide feed unit, 32 parts of methanol and 0.35 part of sodium hydroxidewere heated to 110° C., kepet stirred, and maintained under pressurecontrolled between 5 and 8 kg/cm². To the heated and stirred solution,88 parts of ethylene oxide was added dropwise. The resultant mixture wasleft aging at for 30 minutes, heated further to 150° C. and 352 parts ofethylene oxide was added dropwise thereto. Thereafter, the resultantmixture was left aging for 1 hour, to produce a 10-mol adduct ofuniterminally methoxylated ethylene oxide. In the same autoclave as usedabove, 47.2 parts of the 10-mol adduct of a uniterminally methoxylatedethylene oxide and 0.62 part of sodium hydroxide were heated to 150° C.To the heated mixture in the autoclave, 616 parts of ethylene oxide wasadded dropwise. The resultant mixture was left aging for 1 hour tocomplete polymerization and produce a uniterminally methoxylatedpolyethylene glycol.

In the same flask as used in Example 9, 663 parts of the uniterminallymethoxylated polyethylene glycol obtained by the reaction mentionedabove and 4.3 parts of sodium hydroxide were heated to 60° C. Thecontents of the flask were kept stirred and 10.0 parts ofepichlorohydrin was quickly added thereto. Then, the resultant mixturewas heated to 95° C. and left aging at this temperature for 2 hours, toproduce a polymer possessing a terminal epoxy group as a reactive group.The molecular weight, Mn, of this polymer, by the GPC test, was found tobe 6,600. The polymer possessing a uniterminal epoxy group as a reactivegroup was dissolved in diethylene glycol, to produce a solution havingan involatile content of 33.3%.

In the same flask as used in Example 9, 90 parts of the solution and 30parts of carbon black (produced by Mitsubishi Chemical Industry Co.,Ltd. and marketed under trademark designation of "Carbon Black MA-7")were left reacting at 150° C. for 5 hours, to produce a diethyleneglycol solution of a carbon black-graft polymer (10).

EXAMPLE 12

44 part of a polymer possessing one epoxy group as a reactive group inthe molecular unit (produced by Nagase Chemical Industry Co., Ltd. andmarketed under trademark designation of "Denacol EX-1") and 20 parts ofcarbon black (MA-100R) were caused to react with each other in the samemanner as in Example 9. The resultant reaction mixture was cooled andthen pulverized to produce a carbon black (11).

EXAMPLE 13

In the same flask as used in Example 9, 100 parts polybutadiene (aproduct of Nippon Soda Co., Ltd. having a molecular weight, Mn, of 3,000and marketed under trademark designation of "NISSO-PB B-3000") wasdissolved in 300 parts of benzene. The resultant solution in the flaskwas kept vigorously stirred at a temperature in the range of 30° to 35°C. and 100 parts of 4% peracetic acid was added dropwise thereto. Theresultant mixture was left reacting for 2 hours. The reaction mixturewas washed first with water, then with an aqueous 5% caustic sodasolution, and again with water and distilled under a vacuum to expelbenzene, to produce a polymer possessing one epoxy group on the averageas a reactive group in the molecular unit.

Then, 45 parts of the polymer possessing one epoxy group on the averageas a reactive group in the molecular unit and 15 parts of the samecarbon black as used in Example 11 were caused to react with each otherin the same manner as in Example 9. The resultant reaction mixture wascooled and then pulverized to produce a carbon black-graft polymer (12).

EXAMPLE 14

By the procedure of Example 9, 40 parts of the polymer possessing anepoxy group as a reactive group and synthesized in Example 9 and 20parts of the same carbon black as used in Example 1 were caused to reactwith each other. The resultant reaction mixture was cooled andpulverized, to produce a carbon black-graft polymer (13).

EXAMPLE 15

The same flask as used in Example 9 was charged with 400 parts ofdeionized water having 0.2 part of polyvinyl alcohol dissolved thereinand further charged with a mixture prepared in advance by dissolving 16parts of benzoyl peroxide in a polymerizable monomer consisting of 189.9parts of styrene and 10.2 parts of glycidyl methacrylate. The resultantmixture was stirred at high rate to produce a homogeneous suspension.Then, the suspension, with nitrogen gas kept blown therein, was heatedto 80° C., kept stirred at the same temperature for 5 hours to effectpolymerization reaction, and then cooled to produce a polymersuspension. This polymer suspension was separated by filtration, washedand then dried to produce a polymer possessing two epoxy groups on theaverage as reactive groups in the molecular unit. The molecular weight,Mn, of this polymer, by the GPC test, was found to be 5,500.

In the same manner as in Example 9, 40 parts of the polymer possessingtwo epoxy groups on the average as reactive groups in the molecular unitand 20 parts of the same carbon black as used in Example 4 were causedto react with each other, cooled, and pulverized to produce a carbonblack-graft polymer (14).

Control 3

In the same manner as in Example 9, 45 parts of the same polystyrenepossessing no reactive group as used in Example 10 and 15 parts of thesame carbon black as used in Example 4 were kneaded, then cooled, andpulverized to produce a carbon black-graft polymer (3) for comparisonwherein the carbon black component and the polymer component were notsubstantially bonded to each other.

Control 4

The same flask as used in Example 9 was charged with 400 parts ofdeionized water having 0.2 parts of polyvinyl alcohol dissolved thereinand was further charged with a mixture prepared in advance by dissolving16 parts of benzoyl peroxide in a polymerizable monomer consisting of149 parts of styrene and 51 parts of glycidyl methacrylate. Theresultant mixture was stirred at high rate to produce a homogeneoussuspension. Then, the suspension, with the nitrogen gas kept blowntherein, was heated to 80° C., kept stirred at this temperature for 5hours to effect polymerization reaction, and then cooled, to produce apolymer suspension. This polymer suspension was separated by filtration,washed, and then dried to produce a polymer possessing an epoxy group asa reactive group. The molecular weight, Mn, of this polymer, by the GPCtest, was found to be 5,000.

In the same mill as used in Example 1, 40 parts of a polymer possessing10 epoxy groups on the average as reactive groups in the molecular unitand 20 parts of the same carbon black as used in Example 4 were kneadedat 160° C. at a rate of 100 rpm to effect reaction, then cooled, andpulverized to produce a carbon black-graft polymer (4) for comparison.

EXAMPLE 16

The carbon black-graft polymers (8) through (14) and the carbonblack-graft polymers (1), (3), and (4) for comparison obtainedrespectively in Example 9 through 15 and Controls , 3, and 4 were testedfor dispersibility in toluene and water. The results were as shown inTable 2.

                  TABLE 2                                                         ______________________________________                                        Amount (parts   pH of   Dis-                                                  of polymer per  carbon  persibitilty                                                                            Dispersibility                              100 parts of    black   in toluene                                                                              in water                                    carbon black    used    (Note 1)  (Note 1)                                    ______________________________________                                        Example 9                                                                             200             3.5   ○                                                                              --                                      Example 10                                                                            200    (Note 2) 3.5   ○                                                                              --                                      Example 11                                                                            100             3.0   --      ○                                Example 12                                                                            220             3.5   --      ○                                Example 13                                                                            300             3.0   ○                                                                              --                                      Example 14                                                                            200             7.5   Δ --                                      Example 15                                                                            200             3.5   Δ --                                      Control 1                                                                             250             3.5   X       --                                      Control 3                                                                             300             3.5   X       --                                      Control 4                                                                             200             3.5   X       --                                      Referential                                                                           0               3.5   X       X                                       Experiment                                                                    (Note 3)                                                                      ______________________________________                                         (Note 1) The condition of dispersion was rated with respect to a              dispersion possessing a carbon black content of 5%. The rating was made o     the threepoint scale, wherein the circle ( ○ ) stands for highly       desirable dispersion evinced by absence of conglomeration, the triagngle      (Δ) for presence of slight conglomeration, and the cross (X) for        poor dispersion evinced by conglomeration of substantially all solid          particles and sedimentation of carbon black on the bottom of the containe     (Note 2) In the total of 200 parts of polymer a polymer possessing            reactive group accounted for 100 parts.                                       (Note 3) Referential Experiment represents a case of exclusive use of the     same carbon black as in Example 4.                                       

EXAMPLE 17

In a Henschel mixer, 30 parts of the carbon black-graft polymer (1)obtained in Example 1, 70 parts of a styrene-butyl methacrylatecopolymer (produced by Sanyo Chemical Industries Co., Ltd. and marketedunder trademark designation of "Himer SBM 73"), and 2 parts of a chargecontrol agent (product of Hodogaya Chemical Co., Ltd. and marketed undertrademark designation of "Aizen Spiron Black TRH") were stirred and,then in a roll mill, they were kneaded at 160° C. for 20 minutes. Theresultant mixture was colled and coarsely pulverized with a continuousvibration mill. Subsequently, the coarse powder was finely pulverizedwith a jet mill and classified to obtain a toner (1) 3 to 15 μm inparticle diameter for the development of electrostatic charge images. Adeveloping agent (1) was obtained by uniformly mixing 5 parts of thetoner (1) mentioned above with 95 parts of iron powder 50 to 80μ inaverage particle diameter as a carrier.

In a copying machine (produced by Ricoh Company Ltd. and marketed undertrademark designation of "Ricopy FT-4630"), this developing agent wasused to develop a latent image. Consequently there was obtained asdeveloped image with clear outlines and very sharp contrast. From thisdeveloped image, more than 200,000 copies of substantially the samedesirable quality were produced.

EXAMPLE 18

A toner (2) 5 to 15 μm in particle diameter for the development ofelectrostatic charge images was obtained by repeating the procedure ofExample 17, excepting 30 parts of the carbon black-graft polymer (8)obtained in Example 9, 70 parts of a styrene type resin (produced byEsso Petro-Chemical Co., Ltd. and marketed under trademark designationof "Picorastic D-125"), and 2 parts of the same charge control agent asused in Example 17 were used instead during the mixing in the Henschelmixer. From this toner (2), a developing agent (2) was producedsimilarly.

In the same test as in Example 17, this developing agent (2) produced avisible image of clear outlines and very sharp contrast. From thisdeveloped image, more than 200,000 copies of substantially the samedesirable quality were produced.

EXAMPLE 19

A toner (3) 5 to 15 microns in particle diameter for the development ofelectrostatic charge images was obtained by repeating the procedure ofExample 17, excepting 30% parts of the carbon black-graft polymer (9)obtained in Example 10, 70 parts of an epoxy resin (produced by ShellChemicals Inc. and marketed under trademark designation of "Epon 1004"),and 2 parts of the same charge control agent as used in Example 17 wereused instead during the mixing with the Henschel mixer. A developingagent (3) was produced similarly from the toner (3).

In a copying machine (produced by Mita Industrial Company, Ltd. andmarketed under product code of "DC-113"), this developing agent (3) wasused to develop a latent image. Consequently, there was obtained avisible image of clear outlines and very sharp contrast. From thisdeveloped image, there were obtained more than 200,000 copies ofsubstantially the same desirable quality.

EXAMPLE 20

A toner (4) 5 to 15 microns in particle diameter for the development ofelectrostatic charge images was obtained by repeating the procedure ofExample 17, excepting 30 parts of the carbon black-graft polymer (2)obtained in Example 2, 68.5 parts of the same styrene-butyl methacrylatecopolymer as used in Example 17, 1.5 parts of a low molecularpolyethylene (produced by Mitsui Petrochemical Industries, Ltd. andmarketed under trademark designation of "Mitsui Hi-wax 4052E"), and 3parts of a charge control agent (produced by Orient Chemical IndustriesLtd. and marketed under the trademark designation of "Bontron S-32")were used instead during the mixing in the Henschel mixer. From thistoner (4), a developing agent (4) was produced similarly.

When this developing agent (4) was subjected to the same evaluation asin Example 19, there was obtained a developed image with clear outlinesand very sharp contrast. From this developed image, more than 200,000copies cf substantially the same desirable quality were obtained.

EXAMPLE 21

A toner (5) 5 to 17 microns in particle diameter for the development ofelectrostatic charge images was obtained by repeating the procedure ofExample 17, excepting 30 parts of the carbon black-graft polymer (5)obtained in Example 5, 40 parts of a polyester resin (produced byDai-Nippon Ink & Chemicals, Inc. and marketed under trademarkdesignation of "PLASDIC-S1001"), 30 parts of the same styrene-butylmethacrylate copolymer as used in Example 17, and 2 parts of the samecharge control agent as used in Example 17 were used instead during themixing in the Henschel mixer. From this toner (5), a developing agent(5) was similarly prepared. When this developing agent was subjected tothe same test as in Example 17, there was obtained a developed imagewith clear outlines and very sharp contrast. From this developed image,more than 200,000 copies of substantially the same desirable quality.

EXAMPLE 22

A toner (6) 6 to 18 microns for the development of electrostatic chargeimages was obtained by repeating the procedure of Example 17, excepting40 parts of the polystyrene-containing carbon black-graft polymer (7)obtained in Example 7, 60 parts of the same styrene-butyl methacrylatecopolymer as used in Example 17, and 2 parts of the same charge controlagent as used in Example 17 were used instead during the mixing in theHenschel mixer. From this toner (6), a developing agent (6) wassimilarly prepared.

When this developing agent (6) was subjected to the same test as inExample 19, there was obtained a developed image with clear outlines andvery sharp contrast. From this developed image, more than 200,000 copiesof substantially the same desirable quality were produced.

EXAMPLE 23

A toner (7) 5 to 15 microns in particle diameter for the development ofelectrostatic charge images was obtained by kneading 90 parts of thepolymer possessing an oxazoline group as a reactive group and obtainedin Example 1, 10 parts of the same carbon black as used in Example 1,and 2 parts of the same charge control agent as used in Example 17 inthe same mill as used in Example 1 at 160° C. at a rate of 100 rpm toeffect reaction, then cooling the resultant reaction mixture, andpulverizing and classifying the resultant mixture.

A developing agent (7) was prepared by uniformly mixing 3 parts of thetoner (7) mentioned above with 97 parts of a ferrite type carrier 50 to80 μm in particle diameter. When this developing agent (7) was subjectedto the same test as in Example 17, there was obtained a developed imagewith clear outlines and very sharp contrast. From this developed image,more than 200,000 copies of substantially the same desirable qualitywere produced.

EXAMPLE 24

A toner (8) 5 to 15 microns in particle diameter for the development ofelectrostatic charge images was obtained by repeating the procedure ofExample 23, excepting 20 parts of the polymer possessing an epoxy groupas a reactive group and obtained in Example 9, 10 parts of the samecarbon black as used in Example 4, 70 parts of the same styrene-butylmethacrylate copolymer as used in Example 17, and 3 parts of the samecharge control agent as used in Example 17 were used instead during themixing in the same mill as used in Example 23. A developing agent (8)was prepared by uniformly mixing 4 parts of toner (8) mentioned aboveand 96 parts of iron powder carrier. When this developing agent (8) wassubjected to the same test as in Example 19, there was obtained adeveloped image with very sharp contrast. From this developed image,more than 200,000 copies of substantially the same desirable qualitywere produced.

EXAMPLE 25

In a blender, 30 parts of the carbon black-graft polymer (8) obtained inExample 9, 70 parts of the same styrene-butyl methacrylate copolymer asused in Example 17, 2 parts of the same charge control agent as inExample 17, and 40 parts of a magnetic powder (produced by Toda IndustryCo., Ltd, and marketed under trademark designation of "Ferrite EPT-500")were thoroughly mixed and, then in a roll mill, they were heated andkneaded at 150° C. for 15 minutes. The resultant mixture was cooled,coarsely pulverized with a hammer mill, and finely pulverized in an airjet type fine pulverizer and classified in draft to obtain a powder 8 to25 μm in particle diameter. A one-component magnetic toner was producedby mixing this powder with 0.4 part of hydrophobic colloidal silica(produced by Japan Aerosol Co., Ltd. and marketed under product code of"R-972") in a sample mill.

When the one-component magnetic toner was used in a commerciallyavailable copying machine (produced by Canon Inc. and marketed underproduct code of "NP-150"), to develop a latent image, there was obtaineda developed image with clear outlines and very sharp contrast.

From this developed image, more than 200,000 copies of substantially thesame desirable quality were produced.

Control 5

A toner (1) for comparison for the development of electrostatic chargeimages was obtained by repeating the procedure of Example 17, excepting10 parts of the same carbon black as used in Example 1 was used in theplace of 30 parts of the carbon black-graft polymer (1) obtained inExample 17. From this toner (1) for comparison, a developing agent (1)for comparison was similarly prepared.

When this developing agent (1) for comparison was subjected to the sametest as in Example 17, there was obtained a developed image in whichserious fogging was produced in the non-picture portion to impair theclarity of the image. The photoconductor was seriously smeared after thedevelopment of image was repeated.

Control 6

A toner (2) for comparison for the development of electrostatic chargeimages was obtained by repeating the procedure of Example 18, exceptingthe carbon black-graft polymer (1) for comparison obtained in Control 1was used in the place of the carbon black-graft polymer (2) obtained inExample 2. From this toner (2) for comparison, a developing agent (2)for comparison was similarly prepared. When this developing agent (2)was subjected to the same test as in Example 1, there was obtained adeveloped image in which serious fogging was produced in the non-pictureportion to impair the clarity of the image. The photoconductor portionwas seriously smeared after the development of image was repeated.

EXAMPLE 26

An unsaturated polyester having an acid number of 23 was obtained bysubjecting 50 parts of isophthalic acid, 70 parts of maleic anhydride,34 parts of ethylene glycol, and 38 parts of propylene glycol toesterification reaction under a current of nitrogen gas at 200° C. for22 hours. An unsaturated polyester resin (hereinafter referred to as"unsaturated polyester resin (1)") was obtained by combining 40.6 partsof this unsaturated polyester with 50.4 parts of styrene.

Then a thermosetting resin composition of the present invention(hereinafter referred to as "resin composition (1)" was produced bymixing 100 parts of the unsaturated polyester resin (1) with 18 parts ofthe carbon black-graft polymer (1) obtained in Example 1.

The produced resin composition (1) was stirred with 1.3 parts of t-butylperoxybenzoate, 4 parts of zinc stearate, and 100 parts of calciumcarbonate to produce a paste. In an impregnating liquid obtained bymixing this paste with 1.0 part of magnesium oxide, 70.7 parts of glassfibers 25 mm in length were immersed. The wet glass fibers werecompressed into a sheet between two polyethylene sheets and left agingat 40° C. for 40 hours to produce a sheet molding compound (SMC). In amold 300 mm×100 mm in cavity size, this SMC was pressed at 145° C. under50 kg/cm² of pressure for 4 minutes to produce a flat sheet 2 mm inthickness. When this molded product and the mold were observed withunaided eyes, no uneven coloration was found in the product and no smearin the mold. When the SMC was tested for shrinkage by molding inaccordance with the method of JIS K-6911, the shrinkage of this SMC wasfound to be 0.09%. When the molded product was tested for surface glosswith a surface gloss meter, the gloss as expressed in terms ofreflectance at a measuring angle of 60 degrees was found to be 85.3%.The result indicates that the molded product was excellent in surfacesmoothness.

EXAMPLE 27

A thermosetting resin composition of the present invention (hereinafterreferred to as "resin composition (2)") was obtained by repeating theprocedure of Example 26, excepting the carbon black-graft polymer (7)obtained in Example 7 was used in the place of the carbon black-graftpolymer (1) obtained in Example 1. From the resin composition (2), amolded product was obtained by following the procedure of Example 26.When this molded product and the mold were observed with unaided eyes,no uneven coloration was found in the molded product and no smear in themold. When the molded product was tested for shrinkage by molding andfor surface gloss in the same manner as in Example 26, the shrinkage wasfound to be 0.075% and the gloss to be 84.2%. The results indicate thatthe molded product possessed very high surface smoothness.

EXAMPLE 28

A clear resin solution (hereinafter referred to as "amino resin (1)")was obtained by subjecting a mixture consisting of 600 parts ofbenzoguanamine, 600 parts of melamine, and 1675 parts of 37% formalin inconjunction with 6.7 part of an aqueous 10% sodium carbonate solution toresinification reaction at 80° C. for 90 minutes in a reaction vesselprovided with a thermometer, a stirrer, and a reflux condenser.

In a kneader, 2875 parts of a solution of the amino resin (1) and 780parts of pulp sheet were mixed at temperatures in the range of 45° to55° C. for 30 minutes. The resultant mixture was dried in a hot airdrier at 70° C. for 4 hours. In a ball mill, 100 parts of the dryproduct obtained above, 20 parts of the carbon black-graft polymer (8)obtained in Example 9, 0.15 part of phthalic anhydride, and 0.5 part ofzinc stearate were ground and mixed for 24 hours, to obtain a resincomposition (hereinafter referred to as "resin composition (3)"). Theresin composition (3) was tested for properties by the method set forthin JIS K-6911-1970. The results were as shown in Table 3.

EXAMPLE 29

A clear resin solution (hereinafter referred to as "amino resin (2)")was obtained by subjecting a mixture consisting of 300 parts of melamineand 580 parts of 37% formalin in conjunction with 3.0 parts of anaqueous 28% ammonia solution to resinification reaction at 70° C. for120 minutes in the same reaction vessel as in Example 28.

In a kneader, 514 parts of the amino resin (2) and 220 parts of pulpsheets were mixed at temperatures of 45° to 55° C. for 30 minutes. Theresultant mixture was dried in a hot air direr at 70° C. for 4 hours. Ina ball mill, 100 parts of the dry product, 20 parts of the carbonblack-graft polymer (2) obtained in Example 2, 0.05 part of phthalicanhydride, and 0.5 part of zinc stearate were ground and mixed for 24hours, to produce a thermosetting resin composition (hereinafterreferred to as "resin composition (4)"). The resin composition (4) wastested for properties. The results were as shown in Table 3.

                                      TABLE 3                                     __________________________________________________________________________                      Example and Control                                                                       Control 7                                                                           Control 8                                                   Example 28                                                                          Example 29                                                                          Thermosetting resin                                               Thermosetting resin                                                                       compositions for                                                  compositions                                                                              comparison                                                        (3)   (4)   (1)   (2)                                       __________________________________________________________________________        Cup molding property                                                                        Good with                                                                           Good with                                                                           Uneven                                                                              Uneven                                                      no uneven                                                                           no uneven                                                                           coloration                                                                          coloration                                                  coloration                                                                          coloration                                                                          found found                                     Items                                                                             Bending strength (kg/mm.sup.2)                                                              14.5  15.2  12.1  12.8                                      of test                                                                           Shrinkage by molding (%)                                                                    0.310 0.283 0.401 0.392                                         Post-shrinkage (%)                                                                          0.701 0.685 0.988 0.953                                     __________________________________________________________________________     Method of test:                                                               Cup molding property  The method set forth in JIS K6911-1970 was used wit     necessary modificaions.                                                       Bending strength  The method set forth in JIS K6911-1970 was used with        necessary modifications.                                                      Shrinkage by molding  The method set forth JIS K6911-1970 was used with       necessary modifications.                                                      Post shrinkage  A given molded product was left standing at 70° C.     for 20 hours. The shrinkage which occurred during this standing was           measured by the same method as used for the determination of the shrinkag     by molding.                                                              

From the results of Table 3, it is noted that the thermosetting resincompositions of the present invention enjoyed thorough dispersion ofcarbon black and excelled in coloring property, mechanical strength, andshrinkage.

EXAMPLES 30 THROUGH 36

Polyester compositions were obtained by mixing 100 parts of polyethyleneterephthalate chips severally with the carbon black-graft polymers (1),(2) and (4) through (8) obtained in Examples 1, 2, 4, 5, 7, 9, and 6.

The polyester compositions were melted at 290° C. and extruded intosheets, subsequently biaxially stretched at a longitudinal elongationratio of 350% and a lateral elongation ratio of 400%, and heat set at200° C. to produce films 15 microns in thickness.

EXAMPLE 37

In a reaction vessel, 100 parts of dimethyl terephthalate and 70 partsof ethylene glycol were combined with 0.035 part of manganese acetatetetrahydrate and the resultant mixture was heated and, at the same time,distilled to effect expulsion of methanol, to completeinteresterification reaction.

Then, the interesterification product, 0.03 part of trimethyl phosphateand 0.03 part of antimony trioxide added thereto and 5 parts of anethylene glycol solution of the carbon black-graft polymer (6) preparedin Example 6 further added thereto were subjected to polycondensation bythe conventional method, to produce a polyester composition.

This polyester composition was processed to produce a film by followingthe procedure of Examples 30 through 36.

The films of Examples 30 through 36 and Example 37 were tested forcoarse grains and film surface roughness by the methods to be describedlater on. The results were as shown in Table 4.

Control 9

A polyester film for comparison was obtained by following the procedureof Example 37, excepting diethylene glycol slurry of untreated carbonblack #45 was used in the place of the diethylene glycol solution ofcarbon black graft polymer (6) prepared in Example 9. The film forcomparison was tested for coarse grains and film surface roughness. Theresults are shown in Table 4.

Method for evaluation of film

(1) Coarse grains

Under a microscope using polarized transmitting light, a given film wasconglomerated particles of carbon black occurring in the portionirradiated with the polarized light and exceeding 5 μm in major diameterwere counted. Based on the number of the conglomerated particles, thecoarse grains were rated on the four-grade scale, wherein:

Super grade: The number of conglomerated particles is less than 10/50cm².

First grade: The number of conglomerated particles is between 10 and20/50 cm².

Second grade: The number of conglomerated particles is between 20 and50/50 cm².

Third grade: The number of conglomerated particles is not less than50/50 cm².

A film rated as super grade or first grade is accepted for practicaluse.

(2) Surface coarseness

This property was determined by measurement with a surface roughnesstester produced by Sloan corp., using a touch needle 12.5μ in diameterunder contact pressure of 50 mg.

                  TABLE 4                                                         ______________________________________                                                           Surface coarseness                                                  Coarse particle                                                                         (micron)                                                   ______________________________________                                        Example                                                                       30         Super grade 0.011                                                  31         Super grade 0.020                                                  32         Super grade 0.009                                                  33         Super grade 0.015                                                  34         Super grade 0.013                                                  35         First grade 0.025                                                  36         First grade 0.023                                                  37         Super grade 0.010                                                  Control                                                                        9         Third grade 0.050                                                  ______________________________________                                    

The films obtained in Examples 30 through 37 invariably possessed onlyfew coarse particles and highly smooth surfaces. In the case of the filmof Control 9, the number of coarse particles was large and the sheet ofresin during the course of conversion into film sustained ruptures andthe conversion itself proceeded with difficulty because the carbon blackused therein had not undergone the surface treatment.

EXAMPLES 38 THROUGH 44 AND CONTROL 10

A homogeneous solution was obtained by stirring 30 parts of a saturatedpolyester resin (produced by Toyo Boseki Co., Ltd. and marketed undertrademark designation of "Vylon 200") as a binder in a solventconsisting of 30 parts of toluene, 10 parts of methylethyl ketone, 20parts of butyl acetate and 10 parts of cyclohexanone. Then, in separateportions of this solution, the carbon black-graft polymer (1), (2), (4),(5), (7), (8) and (6) obtained respectively in Examples 1, 2, 4, 5, 7,9, and 6 and the same carbon black as used in Example 1 added in theamounts indicated in Table 5 were thoroughly stirred, to produce carbonblack-containing coating compositions (1) through (7) and a carbonblack-containing coating compositions (1) for comparison.

The carbon black-containing coating compositions were applied onaluminum sheets each in an amount calculated to produce a dry layer 25microns in thickness and dried at room temperature to obtain coats. Thecoats thus formed were tested for film-forming property. The resultswere as shown in Table 5.

                                      TABLE 5                                     __________________________________________________________________________                                 Example              Control                            Example               38 39 40 41 42 43 44 10                          __________________________________________________________________________           Carbon black-containing coating composition                                                         (1)                                                                              (2)                                                                              (3)                                                                              (4)                                                                              (5)                                                                              (6)                                                                              (7)                                                                              (1) for                                                                       comparison                  Proportion                                                                           Carbon black-graft polymer (1)                                                                      3                                                of carbon                                                                            Carbon black-graft polymer (2)                                                                         4.5                                           black- Carbon black-graft polymer (4)                                                                            6                                          containing                                                                           Carbon black-graft polymer (5) 4.5                                     coating                                                                              Carbon black-graft polymer (7)    7.5                                  composition                                                                          Carbon black-graft polymer (8)       4.5                               contained                                                                            Carbon black-graft polymer (6)*         6                              (parts)                                                                              Carbon black (MA-600)                      1.5                                Bilon 200             30 30 30 30 30 30 30 30                                 Solvent               70 70 70 70 70 70 70 70                          Coat   Coloring property     ○                                                                         ○                                                                         ○                                                                         ○                                                                         ○                                                                         ○                                                                         ○                                                                         X                           properties                                                                           Gloss                 83 85 80 82 82 85 83 75                                 Adhesiveness          10 10 10 10 10 10 10 8                                  Frictional coefficient                                                                              0.27                                                                             0.29                                                                             0.32                                                                             0.31                                                                             0.29                                                                             0.28                                                                             0.31                                                                             0.38                        Solution stability           ○                                                                         ○                                                                         ○                                                                         ○                                                                         ○                                                                         ○                                                                         ○                                                                         X                           __________________________________________________________________________     *1: Dieylene glycol solution (carbon black content 25%)                  

It is clearly noted from Table 5 that carbon black-containing coatingcompositions according with the present invention showed highlysatisfactory dispersibility and the coats formed with these compositionspossessed uniform coloring property and excelled in adhesiveness andlubricity.

EXAMPLE 45 AND CONTROL 11

In MEK, a vinyl chloride-vinyl acetate copolymer (produced by NipponZeon Co., Ltd. and marketed under product code of "400X-110A") as abinder, a polyurethane (produced by Japan Polyurethane Co., Ltd. andmarketed under trademark designation of "Nipporan 2301"), and apolyisocyanate (produced by Japan Polyurethane Co., Ltd. and marketedunder trademark designation of "Coronate L") were dissolved in theamounts indicated in Table 6. In the resultant solutions, the carbonblack-graft polymer (1) obtained in Example 1 and carbon black (Asahi#60) added thereto in the amounts indicated in Table 6 were thoroughlystirred, to produce a carbon black-containing coating composition (8)and a carbon black-containing coating composition (2) for comparison.

On polyethylene terephthalate films, the carbon black-containing coatingcompositions were applied each in an amount calculated to produce a drylayer 1.5 microns in thickness. The applied layers of the compositionswere dried at room temperature to product coats, which were tested forfilm-forming property. The results were as shown in Table 6.

                  TABLE 6                                                         ______________________________________                                                         Example 45                                                                             Control 11                                          ______________________________________                                        Carbon black-containing                                                                          (8)        (2) for                                         coating composition           comparison                                      Composition of Carbon black-                                                  containing coating composition                                                (part)                                                                        Colored microfine globular                                                                       60                                                         particle (1)                                                                  Carbon black (Asahi#60)       30                                              400X-110A          17         30                                              Nippolan 2301      9          15                                              Coronate L         14         25                                              Methylethyl ketone 300        300                                             Quality of coat                                                               Antistatic property                                                                              1.5 × 10.sup.4                                                                     8.5 × 10.sup.4                            Frictional coefficient                                                                           0.25       0.34                                            Wear Resistance    ○   X                                               Stability of solution to                                                                         ○   X                                               withstand storage                                                             ______________________________________                                    

It is clearly noted from Table 6 that the carbon black-containingcoating composition of the present invention exhibited highly desirabledispersibility and excelled in antistatic property, slipping property,and wear resistance.

EXAMPLES 46 AND 47 AND CONTROL 12:

In separate portions of an aqueous 40% epoxy ester resin dispersion(produced by Nippon Shokubai Kagaku Kogyo Co., Ltd. and marketed undertrademark designation of "Arolon 5"), the carbon black-graft polymers(4) and (6) obtained in Examples 4 and 6 and the same carbon black asused in Example 4 added in the amounts indicated in Table 7 inconjunction with additives were thoroughly stirred to produce carbonblack-graft polymer-containing coating compositions (9) and (10) and acarbon black-containing coating composition (3) for comparison.

The carbon black-graft polymer-containing and carbon black-containingcoating compositions are applied on polished soft steel sheets each inan amount calculated to produce a dry layer 30 microns in thickness. Theapplied layers were dried at 60° C. for 20 minutes to form coats, whichwere tested for film-forming property. The results were as shown inTable 7.

                  TABLE 7                                                         ______________________________________                                                          Example Control                                             Example             46     47     12                                          ______________________________________                                        CB-containing coating composition                                                                 (9)    (10)   (3) for                                                                       comparison                                  Proportion                                                                             Carbon black-graft                                                                           4.8                                                   of CB-   polymer (4)                                                          containing                                                                             Carbon black-graft    4.8                                                     polymer (6)*.sup.1                                                            Carbon black               1.2                                                (MR-100R)                                                            Composition                                                                            5              100    100  100                                       contained                                                                              Cobalt naphthenate                                                                           0.3    0.3  0.3                                       (parts)  104*.sup.2     0.6    0.6  0.6                                       Coat     Coloring Property                                                                            ○                                                                             ○                                                                           X                                         Properties                                                                             Gloss          94     95   90                                                 Adhesiveness   10     10   9                                                  Corrosionproofness                                                                           1-2    2-3  4-5                                       Solution stability  ○                                                                             ○                                                                             X                                           ______________________________________                                         *.sup.1 Diethylene glycol solution (carbon black content 25%)                 *.sup.2 2,4,7,9Tetramethyl-5-decyl-4,7-diol (produced by Nisshin Chemical     Co., Ltd.)                                                               

It is clearly noted from Table 7 that the carbon black-graftpolymer-containing coating composition of the present invention showedhighly desirable dispersibility even when water was used as a medium andthe coat formed with the composition possessed coloring property andexcelled in adhesiveness, lubricity, etc.

In the test mentioned above, the properties of coat were determined bythe following methods.

Coloring property

This property was determined by visual examination of the condition ofcoloration of a given coat and rating condition on the two-point scale,wherein the circle () stands for high gloss of coat due to uniformcoloration and the cross (X) for suppressed gloss of coat due to uniformcoloration.

Gloss

This property was determined by measuring the reflectance of light at afixed angle of 60°.

Adhesiveness

This property was determined by incising perpendicularly intersectinggrooves at intervals of 1 mm to form 100 squares, applying an adhesivetape fast on the film containing the grooves enclosing the squares,abruptly separating the grooves enclosing the squares, abruptlyseparating the adhesive tape, and rating the number of unseparatedsquares of the 10-point scale.

Frictional coefficient

This property was determined by measuring the dynamic frictionalcoefficient, μ, (3.3 cm/sec. of a stainless steel ball with a surfaceproper testing machine.

Antistatic property

This property was determined by a procedure of allowing a given coatedarticle to stand for 24 hours under an atmosphere kept at 25° C. and 60%RH and, at the end of the standing, measuring the surface electricresistance of the coated article.

Wear resistance:

This property was determined by causing a given coated article toreciprocate 100 times in a Gakushin type dye fastness testing machine inaccordance with the method set forth in JIS L-1084 45R and subsequentlyvisually examining the condition of wear caused on the coated article bythe friction on the two-point scale, wherein the circle () stands forabsence of wear and the cross (X) for presence of wear.

Corrosion Proofness:

This property was determined by exposing a sample at the end of thespray, containing cross cuts to 72 hours' salt spray and, measuringwidths (mm) of rust-forming portions in the cross cuts and rating theresults of measurement.

Solution stability:

This property was determined by preserving a given carbon black-graftpolymer-containing coating composition in a room kept at 25° C. for 6months and, after the standing, visually examining a change in thecondition of the solution, and rating the found change on the two-pointscale, wherein the circle () stands for absence of change and the cross(X) for occurrence of precipitate of carbon black.

EXAMPLE 48

Carbon black dispersions (I) through (IV) and carbon black dispersions(I) and (II) for comparison were obtained by stirring the carbonblack-graft polymers (1), (2),(8) and (9) obtained in Examples 1, 2, 9and 10 and the carbon black-graft polymers (1) and (2) obtained inControls 1 and 2 severally with a 1/1 mixed solvent of toluene/ethylacetate added thereto in an amount calculated to give a carbon blackconcentration of 30% in a stirrer provided with a propeller blade. Thedispersions were tested for particle diameter of carbon black by thecentrifugal sedimentation method. During the course of thedetermination, the carbon black concentration of a sample suspension wasadjusted with a 1/1 mixed solvent of toluene/ethyl acetate so as toallow the light transmittance would fall in the optimum range. Thenumerical values found by the test are shown in conjunction with theparticle diameter of untreated carbon black in Table 8.

                  TABLE 8                                                         ______________________________________                                        Carbon black dispersion                                                                       Particle diameter (μm)                                     ______________________________________                                        (I)             0.06                                                          (II)            0.05                                                          (III)           0.04                                                          (IV)            0.05                                                          (I) for comparison                                                                            1.1                                                           (II) for comparison                                                                           1.4                                                           Untreated carbon black                                                                        5.0                                                           ______________________________________                                    

When the carbon black dispersions (I) through (IV) were used as pigmentpastes for acryl lacquers, there were obtained colored lacquers enjoyinghighly desirable stability of carbon black dispersion. In contrast, acolored lacquers similarly obtained by using carbon black dispersionsfor comparison were observed to entail separation of pigment.

EXAMPLE 49

The same flask as used in Example 1 was charged with 217 parts oftoluene. The solvent in the flask, with nitrogen gas kept blown therein,was heated to 90° C. To the hot solvent in the flask, a mixture preparedin advance by dissolving 5.44 parts of thioglycolic acid and 1.32 partsof azobisisobutyronitrile in a polymerizable monomer consisting of 480parts of methyl methacrylate and 20 parts of n-butyl acrylate was addeddropwise through a dropping funnel over a period of 2 hours. Theresultant mixture was further stirred for 5 hours to effectpolymerization reaction. The molecular weight, Mn, of this polymer, bythe GPC test, was found to be 9,500.

Then, by allowing 185.1 parts of the reaction product (a solutioncontaining a prepolymer possessing a terminal carboxyl group) to reactwith 2.95 parts of 2-p-phenylene-bis-2-oxazoline at 80° C. for 2 hours,there was obtained a solution (nonvolatile content 70%) of a polymerpossessing an oxazoline group as a reactive group.

In a pressure kneader, 40 parts of the solution (nonvolatile content70%) of the polymer and 20 parts of the same carbon black as used inExample 4 were kneaded at 160° C., to produce a carbon black-graftpolymer dispersion, which was labeled as carbon black-graft polymerdispersion (V). The particle diameter of carbon black in thisdispersion, by the same test as in Example 1, was found to be 0.06μm.When the carbon black dispersion (V) was mixed by stirring with aprinting ink vehicle, there was obtained printing ink possessing highlydesirable dispersibility of carbon black.

EXAMPLE 50

In the same flask as used in Example 1, 200 parts of a terminal carboxylgroup-containing linear saturated polyester (a product of NipponShokubai Kagaku Kogyo Co., Ltd. possessing a molecular weight, Mn, of6,000 and an involatile content of 50% and marketed under trademarkdesignation of "Aroplaz OB-63") and 3.60 Parts of2-p-phenylene-bis-2-oxazoline added thereto were heated at 110° C. for 2hours to effect reaction. Consequently, there was obtained a solution(involatile content 50.9%) of a polymer possessing a terminal oxazolinegroup as a reactive group. By kneading 40 parts of the solution(involatile content 50.9%) of the polymer possessing terminal oxazolinegroup and 20 parts of the same carbon black as used in Example 4 underthe same conditions as in Example 1, there was obtained a carbonblack-graft polymer dispersion, which was leveled as carbon black-graftpolymer dispersion (VI). The particle diameter of carbon black in thedispersion, by the same test as in Example 48, was found to be 0.08μm.When 10 parts of the carbon black dispersion (VI) (pigment paste) and 90parts of the same linear saturated polyester as mentioned above weremixed by stirring, there was obtained a black enamel possessing highlydesirable dispersibility of carbon black. This enamel produced a coatingof high gloss.

EXAMPLE 51

The same flask as used in Example 1 was charged with 400 parts ofisopropanol. The contents of the flask, with nitrogen gas kept blowntherein, was heated to the boiling point of isopropanol. To the heatedisopropanol in the flask, a mixture prepared in advance by dissoling 8parts of benzoyl peroxide in a polymerizable monomer consisting of 100parts of hydroxyethyl acrylate, 30 parts of methyl acrylate, 60 parts ofethyl acrylate, and 10 parts of glycidyl methacrylate was added dropwisethrough a dropping funnel over a period of 2 hours. The resultantmixture was further stirred for 5 hours. After 300 part of allisopropanol was expeled, 100 parts of water was added to produce apolymer solution. The molecular weight, Mn, of this polymer, by the GPCtest, was found to be 2,200.

20 parts of the aqueous solution of the polymer possessing an epoxygroup as a reactive group, 20 parts of a water-soluble acryl resin(product of Nippon Shokubai Kagaku Kogyo Co., Ltd. and marketed undertrademark designation of "Arolon 76"), and 20 parts of the same carbonblack as used in Example 4 were kneaded in a pressure kneader at 160° C.to effect reaction. Consequently, there was obtained a carbonblack-graft polymer dispersion, which was labeled as carbon blackdispersion (VII). When this dispersion was diluted with a 1/1 mixedsolvent of isopropanol/water for adjustment of the light transmittanceand then tested for particle diameter by the centrifugal sedimentationmethod, the particle diameter was found to be 0.04 microns. When 60parts of the carbon black dispersion (VII) was diluted by stirring with40 parts of water and used as a water sign pen ink, the pen producedclean unbroken letters even after a total 3,000 letters. The lettersshowed highly satisfactory resistance to water and remained intact evenafter several months' standing. Thus, the pen showed good writingproperty.

EXAMPLES 52 THROUGH 55 AND CONTROLS 13 AND 14 (Kneading)

In the same mill as used in Example 1, a varying combination ofingredients shown in Table 9 was kneaded at 140° C. for 2 minutes. Theresultant blend was then kneaded with an 8-inch a roll at a surfacetemperature of 50°±5° C. in accordance with the method of JIS K-6383, toproduce a rubber composition.

                                      TABLE 9                                     __________________________________________________________________________                     Example       Control                                                         52 53  54 55  13 14                                          __________________________________________________________________________    Rubber component JSR 1500 1)                                                                   100                                                                              100 100                                                                              100 100                                                                              100                                         Carbon black component                                                        Carbon black-graft polymer (1)                                                                 60                                                           Carbon black-graft polymer (2)                                                                    60                                                        Carbon black-graft polymer (3)                                                                        60                                                    Carbon black-graft polymer (8)                                                                           60                                                 Carbon black (MA-600)          30                                             Grafted carbon black (1)          60                                          for comparison                                                                Stearlic acid    1  1   1  1   1  1                                           ZnO              5  5   5  5   5  5                                           Slulfur          1.5                                                                              1.5 1.5                                                                              1.5 1.5                                                                              1.5                                         Vulcanizing agent                                                                              1  1   1  1   1  1                                           __________________________________________________________________________     (Note 1) Styrenebutadiene rubber (produced by Japan synthetic Rubber Co.,     Ltd.)                                                                         (Note 2) Produced by Ouchi Shinko Co., Ltd.                              

(Vulcanization and molding of rubber composition)

The rubber composition obtained by the kneading mentioned above waspress vulcanized at 145° C. for 20 minutes to produce a sheet 2 mm inthickness. (Method for evaluation of properties)

Dispersibility of carbon

This property was determined by the observation of a sample under amicroscope (at 100 magnifications), with the results rated on thefour-point scale, wherein the double circle () stands for uniformdispersion and substantial absence of conglomerated particles exceedingseveral microns, the circle () for sparce occurrence of conglomeratedparticles exceeding several microns, the triangle (Δ) for denseoccurrence of conglomerated particles exceeding several microns andincluding larger particles 20 to 30 microns in diameter, and the cross(X) for dense occurrence of larger particles.

Tensile strength

This property was determined by the method of JIS K-6301, with necessarymodifications.

Wear resistance

This property was determined in accordance with the British Standard,930, Part A9, (1957) with necessary modifications. The results wererated, based on the numerical value of the composition of Control 13taken as 100. The desirability of wear resistance increases with theincreasing numerical value of the property.

Resistance to aging

This property was determined by a procedure of keeping a given moldedarticle of rubber in a gear oven at 100° C. for hours and at the end cfthe standing, testing the molded article for tensile strength. It wasreported in the ratio of retention of the initial magnitude of tensilestrength. The results were as shown in Table 10. It is noted from theresults that the rubber compositions according with the presentinvention, other than those of Controls 13 and 14, invariably exhibitedhighly satisfactory properties.

                  TABLE 10                                                        ______________________________________                                        The test results of properties                                                           Example        Control                                                        52   53      54     55   13    14                                  ______________________________________                                        Dispersibility of                                                                          ⊚                                                                     ⊚                                                                      ⊚                                                                   ⊚                                                                   X     Δ                           carbon                                                                        Tensile strength                                                                           315    285     300  310  150   178                               (kg/cm.sup.2)                                                                 Wear resistance                                                                            113    108     115  114  100   101                               (index)                                                                       Resistance to                                                                              95     90      93   94   53    62                                thermal aging (%)                                                             ______________________________________                                    

EXAMPLE 56

Thermographic transfer inks severally containing the carbon black-graftpolymers (1), (2), (7), (8), and (11) obtained in Examples 1, 2, 7, 9and 12, the carbon black-graft polymers (1) and (2) obtained in Controls1 and 2, and the same carbon black as used in Example 4 in theproportions indicated in Table 11 were prepared.

EXAMPLE 57

A polymer possessing a molecular weight of Mn=4,000 and possessing anN-hydroxyalkylamide group as a reactive group was obtained by repeatingthe procedure of Example 1, excepting 120 parts of styrene, 76 parts ofstearyl acrylate, and 4 parts of N-hydroxyethyl methacrylamide were usedin the place of the polymerizable monomers used in Example 1. In thesame mill as used in Example 1, a carbon black graft polymer wasobtained by repeating the procedure of Example 1, excepting 100 parts ofthe polymer thus obtained, 70 parts of carnauba wax which is componentof ink for thermographic transfer, and 20 parts of the same carbon blackas used in Example 1 were used instead.

                  TABLE 11                                                        ______________________________________                                                Carbon black-                                                                 graft polymer                                                                              Wax                                                      Thermographic        A-                A-                                     transfer ink         mount             mount                                  (No.)     No.        (parts) Kind      (parts)                                ______________________________________                                        [1]       (1)        30      Carnauba wax                                                                            70                                     [2]       (2)        45      Paraffin wax                                                                            55                                     [4]       (7)        50      Carnauba wax                                                                            50                                     [5]       (8)        45      Carnauba wax                                                                            55                                     [6]       (11)       47      Paraffin wax                                                                            53                                     [1] for   (1) for    30      Carnauba wax                                                                            70                                     comparison                                                                              comparison                                                          [2] for   (2) for    19      Carnauba wax                                                                            81                                     comparison                                                                              comparison                                                          [3] for   CB untreated                                                                             15      Carnauba wax                                                                            85                                     comparison                                                                              carbon black                                                        ______________________________________                                    

The inks of No. [1], [2], [4], [5], and [6] and those of No. [1] and [2]for comparison were each prepared by stirring the components at 100° C.for 30 minutes and the ink of No. [3] for comparison was prepared bystirring the components at 100° C. for 30 minutes and subsequentlykneading the resultant mixture with a three-roll mill. The carbonblack-graft polymer (15) obtained in Example 57 was used in itsunmodified form as thermographic transfer ink No. (3). This ink wasspread thinly on glass plates and observed under a microscope as to thestate of dispersion of carbon black therein. The results of theobservation were rated on the three-point scale (, Δ, and X). Theresults were as shown in Table 12.

                  TABLE 12                                                        ______________________________________                                        Thermographic                                                                 transfer ink No.                                                                              Dispersibility                                                ______________________________________                                        [2]             ○                                                      [3]             ○                                                      [4]             ○                                                      [5]             ○                                                      [6]             ○                                                      [1] for comparison                                                                            Δ-X                                                     [2] for comparison                                                                            X                                                             [3] for comparison                                                                            Δ                                                       ______________________________________                                    

EXAMPLE 58

The thermographic transfer inks obtained in Example 56 were applied onbiaxially oriented PET films 6 microns in thickness severally in anamount calculated to produce a dry layer 4 microns in thickness. Theapplication was effected by heating a given ink to a temperature properfor the ink thereby converting into a fluid state, and rubbing the fluidink on the film with a tire bar. The thermographic transfer sheets wereeach set in place on a thermal printer and pressed on sheets of ordinarypaper to produce prints. The quality of a produced print was evaluatedwith respect to resolution and occurrence of spots of discontinuity incomponent lines of image. The results were rated on the five-pointscale, wherein 5 stands for good quality and 1 for bad quality. Thescratch strength of the produced image was determined by rubbing theimage surface with a stainless steel bar terminating at one end thereofinto a hemisphere 1.5 mm in diameter under a load of 100 g and measuringthe degree of scratch inflicted on the surface. The results ofmeasurement were rated on the three-point scale (○, Δ, and X). Theresults are shown in Table 13.

                  TABLE 13                                                        ______________________________________                                        Thermographic    Quality of Scratch                                           transfer ink No. used                                                                          print (point)                                                                            strength                                          ______________________________________                                        [1]              5           ○ -Δ                                [2]              5           ○ -Δ                                3]               5          ○                                          [4]              5          ○                                          [5]              5           ○ -Δ                                [6]              5          ○                                          [1] for comparison                                                                             2          Δ-X                                         [2] for comparison                                                                             2          X                                                 [3] for comparison                                                                             3          X                                                 ______________________________________                                    

EXAMPLE 59

An ink ribbon coating agent was prepared by mixing 20 parts of thecarbon black-graft polymer (1) obtained in Example 1, with 100 parts ofpolyurethane (a polyester type polyurethane possessing a molecularweight of about 30,000, obtained from adipic acid, 1,6-hexane diol, andMDI) as a binder component, and 70 parts of a solvent (an equivoluminalmixture of tetrahydrofuran and methylethyle ketone). This ink ribboncoating agent was applied to the rear side of a thermosensitive transfertape and the thermosensitive transfer tape was set in place on a thermalcoating agent for quality. The thickness of the applied coat was about 5microns. The results of the test indicate that the applied coat excelledin both slipping property and antistatic property.

EXAMPLE 60

An ink ribbon coating agent was prepared by mixing 20 parts of thecarbon black graft polymer (8) obtained in example 9, with 100 parts ofpolyurethane (a polyester type polyurethane possessing a molecularweight of about 30,000, obtained from adipic acid, 1,6-hexane diol, andMDI) as a binder component, and 70 parts of a solvent (an equivoluminalmixture of tetrahydrofuran and methylethyle ketone). This ink ribboncoating agent was applied to the rear side of a thermosensitive transfertape and the thermosensitive transfer tape was set in place on a thermalcoating agent for quality. The thickness of the applied coat was about 4microns. The results of the test indicate that the applied coat excelledin both slipping property and antistatic property.

EXAMPLE 61

Back-coating agents were prepared by mixing the carbon black-graftpolymers (1) through (3) and (5), (7), (9) and (10), obtained inExamples 1 through 3 and 5, 7, 10 and 11, the carbon black-graftpolymers (1) and (2) obtained in Controls 1 and 2 and the same carbonblack as used in Example 4 severally with a varying binder component anda varying solvent indicated in Table 14. The back-coating agents wereapplied on video tapes on the rear side to test for performance. Themethod of test is shown below and the results of the test are givencollectively in Table 14.

(Method of test) 1. Preparation of test specimen

(a) Dispersion of carbon black-graft polymer

A given carbon black-graft polymer, a binder component, and a solventwere placed in prescribed amounts in a container and were stirred with apropeller blade stirrer at room temperature for 15 minutes.

(b) Thickness of back-coat layer

A given back-coating agent was applied in an amount calculated toproduce a dry layer about 5 μm in thickness.

2. Test for performacne

(a) Degree of dispersion of carbon black

The diameter (μm) of carbon black particles dispersed in a givenback-coating agent was measured by the centrifugal sedimentation method.

(b) Wear resistance of back-coat layer

This property was determined by keeping a white cotton cloth pressedwith a force of 350 g/cm² against the back coat layer of a video tapeand, at the same time, running the video tape and, at the same time,running the video tape for a prescribed length of time and measuring thedegree of smearing inflicted on the cotton cloth. The results of themeasurement were rated on the four-point scale, wherein the doublecircle () stands for absence of smearing of cotton cloth (absence ofseparation of carbon black), the circle () for slight occurrence ofsmearing of cotton cloth, the triangle (Δ) for fair occurrence ofsmearing of cotton cloth, and the cross (X) for conspicuous occurrenceof smearing of cotton cloth (opulent separation of carbon black).

                                      TABLE 14                                    __________________________________________________________________________                                    Test for performance                          Composition of back-coating agent     Wear                                    Carbon black-                                                                           Binder                Dispersion                                                                          resistance                              graft polymer                                                                           (solids)              of carbon                                                                           of back-coat                            (solids)  (Note)    Solvent     black (um)                                                                          layer                                   __________________________________________________________________________    (1)       Polyurethane                                                                            toluene/MEK/                                                                              0.10  ○                                20 part   10 part   cyclohexanone = 3/3/1                                                         70                                                        (2)       Polyurethane                                                                            toluene/MEK/                                                                              0.08  ⊚- ○              20        10        cyclohexanone = 3/3/1                                                         70                                                        (3)       --        toluene/MEK/                                                                              0.08  ⊚- ○              30                  cyclohexanone = 3/3/1                                                         70                                                        (5)       Vinyl chloridevinyl                                                                     THF/MEK = 1/1                                                                             0.11  ○                                24        acetate copolymer                                                                       70                                                                  6                                                                   (7)       --        toluene/MEK/                                                                              0.05  ⊚                        30                  cyclohexanone = 3/3/1                                                         70                                                        (9)       Polyurethane                                                                            toluene/MEK/                                                                              0.09  ⊚                        20        10        cyclohexanone = 3/3/1                                                         70                                                        (10)      Polyurethane                                                                            toluene/MEK/                                                                              0.10  ○                                20        10        cyclohexanone = 3/3/1                                                         70                                                        (1) for comparison                                                                      Polyurethane                                                                            toluene/MEK/                                                                              0.1   Δ                                 20        10        cyclohexanone = 3/3/1                                                         70                                                        (2) for comparison                                                                      Polyurethane                                                                            toluene/MEK/                                                                              1.5   Δ                                 20        10        cyclohexanone = 3/3/1                                                         70                                                        (3) for comparison                                                                      Polyurethane                                                                            toluene/MEK/                                                                              5.0   X                                       15        15        cyclohexanone = 3/3/1                                                         70                                                        __________________________________________________________________________     (Note)                                                                        Polyurethane: A polyurethane of a molecular weight of about 30,000,           obtained from adipic acid, 1,6hexane diol, and MDI.                           Vinyl chloridevinyl acetate copolymer: a 80/20 vinyl chloride/vinyl           acetate copolymer.                                                       

What is claimed is:
 1. A toner for the development of images ofelectrostatic charge, which toner comprises a carbon black-graft polymerproduced by causing a polymer possessing one to two reactive groups onthe average selected from the class consisting of aziridine group,oxazoline group, N-hydroxyalkylamide group, epoxy group, and thioepoxygroup to react with carbon black, wherein said polymer possesses anumber average molecular weight in the range of 2,000 to 100,000.
 2. Atoner according to claim 1, wherein said polymer possessing a reactivegroup has a number average molecular weight in the range of 500 to1,000,000.
 3. A toner according to claim 2, wherein said polymerpossessing a reactive group is a polymer selected from the groupconsisting of vinyl polymers, polyesters, and polyethers.
 4. A toneraccording to claim 1, wherein the proportion of said polymer possessinga reactive group falls in the range of 1 to 3,000 parts by weightrelative to 100 parts by weight of said carbon black.
 5. A toneraccording to claim 1, wherein a content of carbon black in the tonner isin the range of 1 to 20% by weight.
 6. A thermosetting resin compositionwhich comprises incorporating carbon black graft polymer in athermosetting resin, said polymer produced by causing a polymerpossessing one to two reactive groups on the average selected from theclass consisting of aziridine group, oxazoline group,N-hydroxyalkylamide group, epoxy group, and thioepoxy group to reactwith carbon black, wherein said polymer possesses a number averagemolecular weight in the range of 2,000 to 100,000.
 7. A thermosettingresin composition according to claim 6, wherein said carbon black-graftpolymer is incorporated in an amount in the range of 0.05 to 50% byweight, based on the total amount of said thermosetting resin and saidcarbon black-graft polymer.
 8. A thermosetting resin compositionaccording to claim 7, wherein said thermosetting resin is one memberselected from the group consisting of an unsaturated polyester resin, anepoxy resin, a diallyl phthalate resin, a phenol resin, an amino resin,a polyimide resin and a polyurethane resin.
 9. A thermoplastic resincomposition which comprises carbon black-graft polymer incorporated in athermoplastic resin, said carbon black-graft polymer produced by causinga polymer possessing one to two reactive groups on the average selectedfrom the class consisting of aziridine group, oxazoline group,N-hydroxyalkylamide group, epoxy group, and thioepoxy group to reactwith carbon black, wherein said polymer possesses a number averagemolecular weight in the range of 2,000 to 100,000.
 10. A thermoplasticresin composition accoring to claim 9, wherein said carbon black-graftpolymer is contained in a concentration in the range of 0.001 to 50% byweight in said thermoplastic resin.
 11. A thermoplastic resincomposition according to claim 9, wherein said thermoplastic resin isselected from the group consisting of polyesters, styrene polymers,polyolefins, vinyl chloride polymers, polyurethanes, acrylic polymers,polycarbonates, butyral resins, polyimides, and polyamides.
 12. Athermoplastic resin composition according to claim 9, wherein saidthermoplastic resin is a polyester.
 13. A coating composition, havingincorporated in a binder a carbon black-graft polymer produced bycausing a polymer possessing one to two reactive groups on the averageselected from the class consisting of aziridine group, oxazoline group,N-hydroxyalkylamide group, epoxy group, and thioepoxy group to reactwith carbon black, wherein said polymer possesses a number averagemolecular weight in the range of 2,000 to 100,000.
 14. A coatingcomposition according to claim 13, wherein the carbon black contained insaid carbon black-graft polymer is in the range of 1 to 300 parts byweight, based on 100 parts by weight of said binder.
 15. A coatingcomposition according to claim 13, wherein said binder is at least oneresin selected from the group consisting of thermoplastic resins,thermosetting resins, and reactive resins.
 16. A carbon blackdispersion, having dispersed in a dispersion medium a carbon black-graftpolymer produced by causing a polymer possessing one to two reactivegroups on the average selected from the class consisting of aziridinegroup, oxazoline group, N-hydroxyalkylamide group, epoxy group, andthioepoxy group to react with carbon black, wherein said polymerpossesses a number average molecular weight in the range of 2,000 to100,000.
 17. A carbon black dispersion according to claim 16, whereinthe amount of the carbon black in said carbon black-graft polymer is inthe range of 1 to 80% by weight, based on the amount of said dispersion.18. A carbon black dispersion according to claim 16, wherein saiddispersion medium is at least one member selected from the groupconsisting of water and organic dispersions.
 19. A rubber composition,having incorporated in rubber a carbon black-graft polymer produced bycausing a polymer possessing one to two reactive groups on the averageselected from the class consisting of aziridine group, oxazoline group,N-hydroxyalkylamide group, epoxy group, and thioepoxy group to reactwith carbon black, wherein said polymer possesses a number averagemolecular weight in the range of 2,000 to 100,000.
 20. A rubbercomposition according to claim 19, wherein the amount of said carbonblack-graft polymer incorporated therein falls in the range of 1 to 90%by weight, based on the amount of said composition.
 21. A thermographictransfer ink, which comprises in a binder a carbon black-graft polymerproduced by causing a polymer possessing one to two reactive groups onthe average selected from the class consisting of aziridine group,oxazoline group, N-hydroxyalkylamide group, epoxy group, and thioepoxygroup to react with carbon black, wherein said polymer possesses anumber average molecular weight in the range of 2,000 to 100,000.
 22. Athermographic transfer ink according to claim 21, wherein the amount ofthe carbon black in said carbon black-graft polymer incorporated thereinfalls in the range of 1 to 40% by weight, based on the amount of saidink.
 23. A thermographic transfer ink ribbon coating agent, whichcomprises in a liquid medium a carbon black-graft polymer produced bycausing a polymer possessing one to two reactive groups on the averageselected from the class consisting of aziridine group, oxazoline group,N-hydroxyalkylamide group, epoxy group, and thioepoxy group to reactwith carbon black, wherein said polymer possesses a number averagemolecular weight in the range of 2,000 to 100,000.
 24. A thermographictransfer ink ribbon coating agent accoring to claim 23, wherein theamount of said carbon black-graft polymer incorporated therein falls inthe range of 1 to 60% by weight, based on the amount of said coatingagent.
 25. A back-coating agent for a magnetic recording medium, whichcomprises a carbon black-graft polymer produced by causing a polymerpossessing one to two reactive groups on the average selected from theclass consisting of aziridine group, oxazoline group,N-hydroxyalkylamide group, epoxy group, and thioepoxy group to reactwith carbon black, wherein said polymer possesses a number averagemolecular weight in the range of 2,000 to 100,000.
 26. A back-coatingagent according to claim 25, wherein the amount of said carbonblack-graft polymer incorporated therein falls in the range of 1 to 60%by weight, based on the amount of said coating agent.